Process for concentration of a polypeptide

ABSTRACT

The present invention comprises a method of concentrating a composition comprising a polypeptide of interest and the use of such a concentrated composition for the treatment of diseases in mammals, in particular by subcutaneous injection.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to U.S. Ser. No.12/295,848, filed Oct. 2, 2008, which is a national stage applicationunder 35 U.S.C. §371 of International Application No. PCT/DK2007/000177,filed Apr. 4, 2007, which claims the benefit under 35 U.S.C. §365(b) ofDenmark Patent Application No. PA 200600488, filed Apr. 4, 2006, andDenmark Patent Application No. PA 200600922, filed Jul. 5, 2006. Thecontents of the aforementioned applications are hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a method for concentrating apolypeptide of interest, to the use of a composition comprising aconcentrated polypeptide of interest as a medicament for subcutaneousinjection and to a composition comprising at least 10 mg/ml polypeptideof interest.

BACKGROUND OF THE INVENTION

Some polypeptides are useful as a medicament for the prevention and/ortreatment of certain diseases. The ability to inject a medicamentsubcutaneously is an advantage as it makes it easy for the patients toadminister the medication to themselves.

As there are physiological restrains on how large a volume it ispossible to inject subcutaneously. Thus it is an advantage formedicaments which are to be administered subcutaneously that they areavailable in a high concentration so as to ensure that the patientreceives an adequate amount of the medicament and/or to avoid multiplesubcutaneous injections.

WO 99/37325 discloses methods of treating and preventing disease causedby absence or deficiency of the activity of enzymes belonging to theheme biosynthetic pathway. WO 03/002731 discloses a process forpurification of recombinant porphobilinogen deaminase on an industrialscale and to the use of the purified product for the preparation of amedicament. Similarly, WO 02/099092 and WO 2005/094874 provideslysosomal alpha-mannosidase and therapeutic use hereof. Finally, WO2005/073367 provides a process for purification of aryl sulfatase A anduse of the enzyme in the treatment of metachromatic leukodystrophy.

The present invention relates to a method for concentrating apolypeptide of interest and to the use of a composition comprising aconcentrated polypeptide of interest for the manufacture of a medicamentfor subcutaneous injection into mammal.

SUMMARY OF THE INVENTION

The present invention relates in one aspect to a method of concentratinga composition comprising a polypeptide of interest comprising:

-   -   a) Centrifugation and/or filtration of a composition comprising        a polypeptide of interest    -   b) Concentrating the supernatant or retentate, respectively,        obtained from step a).

In another aspect the present invention relates to a compositioncomprising at least 10 mg/ml polypeptide of interest.

In yet another aspect the present invention relates to use of acomposition comprising 75-250 mg/ml polypeptide of interest for themanufacture of a medicament for subcutaneous injection into a mammal.

In yet another aspect the present invention relates to a method oftreating a mammal for Acute Intermittent Porphyria comprising injectingsubcutaneously a composition of 500-300 mg/ml PBGD.

In yet another aspect the present invention relates a method of treatinga mammal for metachromatic leukodystrophy comprising subcutaneousinjection of a composition of 50-300 mg/ml aryl sulfatase A.

In yet another aspect the present invention relates a method of treatinga mammal for the lysosomal storage disorder alpha-mannosidosiscomprising subcutaneous injection of a composition of 50-300 mg/mllysosomal alpha-mannosidase.

In yet another aspect the present invention relates a method of treatinga mammal for Krabbe disease comprising subcutaneous injection of acomposition of 50-300 mg/ml galactosylcerebrosidase.

DEFINITIONS

For purposes of the present invention, alignments of sequences andcalculation of homology scores may be done using a full Smith-Watermanalignment, useful for both protein and DNA alignments. The defaultscoring matrices BLOSUM50 and the identity matrix are used for proteinand DNA alignments respectively. The penalty for the first residue in agap is −12 for proteins and −16 for DNA, while the penalty foradditional residues in a gap is −2 for proteins and −4 for DNA.

Alignment may be made with the FASTA package version v20u6 (W. R.Pearson and D. J. Lipman (1988), “Improved Tools for Biological SequenceAnalysis”, PNAS 85:2444-2448, and W. R. Pearson (1990) “Rapid andSensitive Sequence Comparison with FASTP and FASTA”, Methods inEnzymology, 183:63-98).

Multiple alignments of protein sequences may be made using “ClustalW”(Thompson, J. D., Higgins, D. G, and Gibson, T J. (1994) CLUSTAL W:improving the sensitivity of progressive multiple sequence alignmentthrough sequence weighting, positions-specific gap penalties and weightmatrix choice. Nucleic Acids Research, 22:4673-4680). Multiple alignmentof DNA sequences may be done using the protein alignment as a template,replacing the amino acids with the corresponding codon from the DNAsequence.

In the context of the present invention, the term “E. C.” (Enzyme Class)refers to the internationally recognized enzyme classification system,Recommendations of the Nomenclature Committee of the International Unionof Biochemistry and Molecular Biology, Academic Press, Inc.

The term “origin” used in the context of amino acid sequences, e.g.proteins, or nucleic acid sequences is to be understood as referring tothe organism from which it derives. Said sequence may be expressed byanother organism using gene technology methods well known to a personskilled in the art. This also encompasses sequences which have beenchemically synthesized. Furthermore, said sequences may comprise minorchanges such as codon optimization, i.e. changes in the nucleic acidsequences which do not affect the amino acid sequence.

DETAILED DESCRIPTION OF THE INVENTION

Polypeptide of Interest

The polypeptide of the present invention may in particular be a hormoneor hormone variant, an enzyme, a receptor or portion thereof, anantibody or portion thereof, an allergen or a reporter. The polypeptideof interest may in particular be an enzyme selected from one of sixmajor enzyme groups, such as an oxidoreductase (E.C. 1), a transferase(E.C. 2), a hydrolase (E.C. 3), a lyase (E.C. 4), an isomerase (E.C. 5),or a ligase (E.C. 6). In a more particular aspect, the polypeptide ofinterest may be an aminopeptidase, amylase, carbohydrase,carboxypeptidase, catalase, cellulase, cellobiohydrolase, chitinase,cutinase, cyclodextrin glycosyltransferase, deoxyribonuclease,endoglucanase, esterase, alpha-galactosidase, beta-galactosidase,glucoamylase, alpha-glucosidase, beta-glucosidase, invertase, laccase,lipase, mannosidase, mutanase, oxidase, pectinolytic enzyme, peroxidase,phospholipase, phytase, polyphenoloxidase, proteolytic enzyme,ribonuclease, transglutaminase, xylanase, or beta-xylosidase.

The polypeptide of interest may in particular be a polypeptide which isuseful as a medicament.

Examples of a suitable polypeptide of interest include but is notlimited to one selected from the group consisting of a phorphobilinogendeaminase, an aryl sulfatase, an alpha-mannosidase and agalactocerebrosidase.

In principle a polypeptide of interest derivable from any source may betreated according to the methods of the present invention.

In a particular embodiment the polypeptide of interest may be of humanorigin. Especially in the context of using a polypeptide of interest forthe manufacture of a medicament which is to be administered to humansmay the polypeptide be of human origin as this may minimize the risk ofunwanted allergic reactions. Natural variations of human polypeptide dueto e.g. polymorphism are in the context of the present inventionincluded in the term “human origin”.

The polypeptide of interest may in particular be produced as arecombinant protein, i.e. a nucleotide sequence encoding the polypeptideof interest may be introduced into a cell for expression of thepolypeptide of interest. The recombinant expression may be homologous orheterologous, i.e. the polypeptide of interest may be expressed in cellwhich it is naturally expressed by (homologous expression) or it may beexpressed by a cell which it is not naturally expressed by (heterologousexpression).

The recombinant polypeptide of interest may be expressed by any cellsuitable for recombinant production of the particular polypeptide ofinterest. Examples of suitable cells include but are not limited toprokaryotic cells, such as an E. coli cell or a Bacillus cell. Examplesof suitable eukaryotic cells include but are not limited to a yeast cellor a mammalian cell such as a Chinese Hamster Ovary (CHO).Alternatively, it may be a human cell.

Suitable host cells for the expression of glycosylated polypeptide arederived from multicellular organisms. Examples of invertebrate cellsinclude plant and insect cells. However, the host cell may also be avertebrate cell, and propagation of vertebrate cells in culture (tissueculture) has become a routine procedure

The term “recombinant polypeptide” or “recombinant polypeptide ofinterest” denotes herein a recombinant produced polypeptide.

Reference to a particular polypeptide of interest includes in thecontext of the present invention also functionally equivalent parts oranalogues of the polypeptide of interest. For example, if thepolypeptide of interest is an enzyme a functionally equivalent part ofthe enzyme could be a domain or subsequence of the enzyme which includesthe necessary catalytic site to enable the domain or subsequence toexert substantially the same enzymatic activity as the full-lengthenzyme or alternatively a gene coding for the catalyst. The term“substantially the same enzymatic activity” refers to an equivalent partor analogue having at least 50%, preferably at least 60%, morepreferably at least 70%, more preferably at least 75%, more preferablyat least 80%, more preferably at least 85%, more preferably at least90%, more preferably at least 95% and most preferably at least 97° k, atleast 98% or at least 99% of the activity of the natural enzyme. Anexample of an enzymatically equivalent analogue of the enzyme could be afusion protein which includes the catalytic site of the enzyme in afunctional form, but it can also be a homologous variant of the enzymederived from another species. Also, completely synthetic molecules thatmimic the specific enzymatic activity of the relevant enzyme would alsoconstitute “enzymatic equivalent analogues”.

Generally, the skilled person will be able to readily devise appropriateassays for the determination of enzymatic activity. For PBGD, however, asuitable assay is described in WO 03/002731, in example 2, as well as inthe experimental sections of the present applications. Aryl sulfhatase,in addition to its natural substrates, is also able to catalyze thehydrolysis of the synthetic, chromogenic substrate, para-Nitrocatecholsulfate (pNCS). The product, para-Nitrocatechol (pNC), absorbs light at515 nm. An assay for determination of aryl sulfatase activity isdescribed in details in WO 2005/073367 and in Fluharty et al. 1978,Meth. Enzymol. 50:537-47. For LAMAN, an appropriate enzyme activityassay is disclosed in WO 02/099092.

Porphobilinogen Deaminase

In one embodiment the polypeptide of interest of the invention may beporphobilinogen deaminase, (also known as porphobilinogen ammonia-lyase(polymerizing)), E.C. 4.3.1.8. (Waldenström 1937, J. Acta. Med. Scand.Suppl. 8). Porphobilinogen deaminase is the third enzyme in the hemebiosynthetic pathway. E.C. 4.3.1.8 has been transferred to E.C.2.5.1.61, so porphobilinogen deaminase (PBGD) is now placed under thisE.C. number.

Porphobilinogen deaminase catalyzes the reaction of 4porphobilinogen+H₂O=hydroxymethylbilane+4 NH₃.

PBDG is important in relation to Acute intermittent porphyria (AIP),which is an autosomal dominant disorder in man caused by a defect (50%reduction of activity) of PBDG (see WO01/07065 for further details inrelation to this).

Porphobilinogen deaminase is in short known as PBGD and in the contextof the present invention these two terms may be used inter-changeablywith one another.

For recombinant expression of PBGD a host cell may in particular be ayeast cell or an E. coli cell.

For a detailed example of construction of a recombinant E. coli cellreference is made to example 1 of WO01/07065 and for construction ofrecombinant HeLa cells and NIH 3T3 cells capable of expressing mousePBGD reference is made to example 6 of WO01/07065.

The term “recombinant porphobilinogen deaminase (rPBGD)” denotes hereina recombinant produced PBGD. In the following, this enzyme and therecombinant human form will be termed “PBGD” and “rhPBGD”, respectively.Within this term is also included an enzymatically equivalent part oranalogue of PBGD. One example of an enzymatically equivalent part of theenzyme could be a domain or subsequence of the enzyme which includes thenecessary catalytic site to enable the domain or subsequence to exertsubstantially the same enzymatic activity as the full-length enzyme oralternatively a gene coding for the catalyst. The term “substantiallythe same enzymatic activity” refers to an equivalent part or analoguesenzyme having at least 50%, preferably at least 60%, more preferably atleast 70%, more preferably at least 75%, more preferably at least 80%,more preferably at least 85%, more preferably at least 90%, morepreferably at least 95% and most preferably at least 97%, at least 98%or at least 99% of the activity of natural human rhPBGD measured in therhPBGD activity assay described in example 2 of WO 03/002731. An exampleof an enzymatically equivalent analogue of the enzyme could be a fusionprotein which includes the catalytic site of the enzyme in a functionalform, but it can also be a homologous variant of the enzyme derived fromanother species. Also, completely synthetic molecules that mimic thespecific enzymatic activity of the relevant enzyme would also constitute“enzymatic equivalent analogues”.

An example of PBGD which may be used in the present invention includesany of those shown in Sequence 1-10 of the present application, or inGenebank no. X04217, X04808 or M95623.

Aryl Sulfatase

In another embodiment of the present invention the polypeptide ofinterest may be an arylsulfatase A.

Arylsulfatase A catalyzes the reaction of a cerebroside 3-sulfate+H₂O=acerebroside+sulphate.

ASA has been purified from a variety of sources including human liver,placenta, and urine. It is an acidic glucoprotein with a low isoelectricpoint. Above pH 6.5, the enzyme exists as a dimer with a molecularweight of approximately 110 kDa. ASA undergoes a pH-dependentpolymerisation forming an octamer at pH 4.5. In human urine, the enzymeconsists of two nonidentical subunits of 63 and 54 kDa. ASA purifiedfrom human liver, placenta, and fibroblasts also consist of two subunitsof slightly different sizes varying between 55 and 64 kDa. As in thecase of other lysosomal enzymes, ASA is synthesised on membrane-boundribosomes as a glycosylated precursor. It then passes through theendoplasmic reticulum and Golgi, where its N-linked oligosaccharides areprocessed with the formation of phosphorylated and sulfatedoligosaccharide of the complex type (Waheed A et al. Biochim BiophysActa. 1985, 847, 53-61, Braulke T et al. Biochem Biophys Res Commun.1987, 143, 178-185). In normal cultured fibroblasts, a precursorpolypeptide of 62 kDa is produced, which translocates viamannose-6-phosphate receptor binding (Braulke T et al. J Biol Chem.1990, 265, 6650-6655) to an acidic prelysosomal endosome (Kelly B M etal. Eur J Cell Biol. 1989, 48, 71-78).

The arylsulfatase A may in particular be of human origin. The length (18amino acids) of the human ASA signal peptide is based on the consensussequence and a specific processing site for a signal sequence. Hence,from the deduced human ASA cDNA (EMBL GenBank accession numbers J04593and X521151) the cleavage of the signal peptide should be done in allcells after residue number 18 (Ala), resulting in the mature form of thehuman ASA. In the following, recombinant arylsulfatase A will beabbreviated rASA, the mature form of arylsulfatase A including themature form of human ASA will be termed “mASA” and the maturerecombinant human ASA will be termed “mrhASA”.

A protein modification has been identified in two eukaryotic sulfatases(ASA and arylsulfatase B (ASB)) and for one from the green alga Volvoxcarteri (Schmidt B et al. Cell. 1995, 82, 271-278, Selmer T et al. Eur JBiochem. 1996, 238, 341-345). This modification leads to the conversionof a cysteine residue, which is conserved among the known sulfatases,into a 2-amino-3-oxopropionic acid residue (Schmidt B et al. Cell. 1995,82, 271-278). The novel amino acid derivative is also recognised asC*-formylglycin (FGly). In ASA and ASB derived from MSD cells, theCys-69 residue is retained. Consequently, it is proposed that theconversion of the Cys-69 to FGly-69 is required for generatingcatalytically active ASA and ASB, and that deficiency of this proteinmodification is the cause of MSD. Cys-69 is referred to the precursorASA which has an 18 residue signal peptide. In the mASA the mentionedcysteine residue is Cys-51. Further investigations have shown that alinear sequence of 16 residues surrounding the Cys-51 in the mASA issufficient to direct the conversion and that the protein modificationoccurs after or at a late stage of co-translational proteintranslocation into the endoplasmic reticulum when the polypeptide is notyet folded to its native structure (Dierks T et al. Proc Natl Acad Sci.1997, 94, 11963-1196, Wittke, D. et al. (2004), Acta Neuropathol.(Berl.), 108, 261-271).

Multiple forms of ASA have been demonstrated on electrophoresis andisoelectric focusing of enzyme preparations from human urine,leukocytes, platelets, cultured fibroblasts and liver. Treatment withendoglycosidase H, sialidase, and alkaline phosphatase reduces themolecular size and complexity of the electrophoretic pattern, whichsuggests that much of the charge heterogeneity of ASA is due tovariations in the carbohydrate content of the enzyme.

The arylsulfatase A may in particular be a form of arylsulfatase A,which is capable of crossing the blood brain barrier and/or a form ofrASA, which possesses specific tags for entry into target cells withinthe brain. In particular, it may be a rASA, which is efficientlyendocytosed in vivo via the mannose-6-phosphate pathway.

Thus the ASA may in particular be covalently bound to a so-called tag,peptides or proteins as vehicles or toxins as vehicles which are capableof increasing and/or facilitating transport of ASA over the blood-brainbarrier and/or across cellular membranes in general (Schwarze et al.,Trends Cell Biol. 2000; 10(7): 290-295; Lindgren et al., TrendsPharmacol. Sci. 2000; 21(3): 99-103). An ASA molecule containing suchpeptide sequences can be produced by expression techniques. The proteintransduction process is not cell type specific and the mechanism bywhich it occurs is not fully elucidated, however, it is believed that ittakes place by some sort of membrane perturbation and penetrationprocess that is receptor independent. A partially unfolded state of themolecule may facilitate the process but is not essential.

An example of a suitable tag includes but is not limited to themannose-6-phosphate tag.

Examples of peptides or proteins as vehicle include but are not limitedto so-called protein-transducing domains. Examples of suitableprotein-transducing domains include but are not limited to thosementioned in WO 2005/073367, which is incorporated herein by reference.Hence the protein-transducing domain may be the 11 residue basic peptidefrom the HIV TAT protein -YGRKKRRQRRR (Schwarze et al., Trends CellBiol. 2000; 10(7): 290-295), a synthetic version of TAT-YARAAARQARA thatconfers more alpha-helicity and amphipathic nature to the sequence (Hoet al., Cancer Res. 2001; 61(2):474-477), a synthetic leader peptidecomposed of poly -R or a mixture of basic -R and -K residues incombination with other amino acids and peptides based on hydrophobicsignal sequence moieties from either beta-3 integrin or Kaposi's sarcomaFGF (Dunican et al. Biopolymers 2001; 60(1): 45-60).

Examples of suitable toxins as vehicles include but are not limited tothose described in WO 2005/073367, which is incorporated herein byreference.

The ASA may in particular comprise a nucleic acid sequence, whichencodes:

-   -   (a) the amino acid sequence of SEQ ID NO:2 in WO 2005/073367;    -   (b) a portion of the sequence in (a), which is enzymatically        equivalent to recombinant human arylsulfatase A    -   (c) an amino acid sequence analogue having at least 75% sequence        identity to any one of the sequences in (a) or (b) and at the        same time comprising an amino acid sequence, which is        enzymatically equivalent to recombinant human arylsulfatase A.

In the present context, an amino acid sequence or a portion of an aminoacid sequence which is a polypeptide capable of hydrolysing an amount ofthe arylsulfatase A substrate pNCS at 37° C. a rate corresponding to aspecific activity of at least 20 U/mg polypeptide (preferably 50 U/mgpolypeptide) when determined in an assay for measuring arylsulfatase Aactivity as described in example 1 of WO 2005/073367, and/or apolypeptide, which is capable of hydrolysing at least 40% of labelledarylsulfatase A substrate, fx. 14C palmitoyl sulfatide, loaded into MLDfibroblasts, when assayed by incubation at a dose level of 25 mU/ml inan assay as described in example 2 of WO 2005/073367.

The ASA may in another embodiment in particular comprise:

-   -   (a) the nucleic acid sequence of SEQ ID NO:1 in WO 2005/073367    -   (b) a portion of the sequence in (a), which encodes an amino        acid sequence, which is enzymatically equivalent to recombinant        human arylsulfatase A    -   (c) a nucleic acid sequence analogue having at least 75%        sequence identity to any one of the sequences in (a) or (b) and        at the same time encoding an amino acid sequence, which is        enzymatically equivalent to recombinant human arylsulfatase A

It may be preferred that the degree of sequence identity between theabove mentioned nucleic acid sequence and SEQ ID NO: 1 of WO 2005/073367is at least 80%, such as at least 85%, at least 90%, at least 95%, atleast 97%, at least 98%, or at least 99%. It may be equally preferredthat the degree of sequence identity between the amino acid sequenceencoded by the above mentioned nucleic acid sequence and SEQ ID NO: 2 WO2005/073367 is at least 80%, such as at least 85%, at least 90%, atleast 95%, at least 97%, at least 98%, or at least 99%.

For the purpose of the present invention it is preferred that thearylsulfatase A is a recombinant enzyme, particularly preferred isrecombinant human arylsulfatase A (rhASA).

It is preferred that rASA is produced in a mammalian cell or cell lineand that said mammalian cell or cell line produces a glycoform of rASA,which is efficiently endocytosed in vivo via the mannose-6-phosphatereceptor pathway. Specifically, the preferred glycoform of rASAcomprises an amount of exposed mannose-6-phosphate, which allowsefficient endocytosis of rASA in vivo via the mannose-6-phosphatepathway.

In a particular embodiment at least one of the produced glycoforms ofrASA is similar to a glycoform produced in CHO cells.

The post translational modification of the cysteine residue in position51 in the mature human arylsulfatase A is relevant for the activity ofthe enzyme. Accordingly, in a preferred embodiment of the presentinvention production of the arylsulfatase A or its equivalent occurs ata rate and under conditions, which result in a product comprising anisoform of the enzyme in which the amino acid corresponding to Cys-69 inSEQ ID NO: 2 of WO 2005/073367 is converted to Formylglycine,corresponding to Fgly-51 in SEQ ID NO: 3 of WO 2005/073367. SEQ ID NO: 4of WO 2005/073367 represents mature human arylsulfatase A after cleavageof the 18 amino acid signal peptide but prior to modification of C-51.

Thus in another embodiment of the present invention the ASA or itsenzymatical equivalent may be selected from the group consisting of

-   -   (a) the amino acid sequence of SEQ ID NO:3 of WO 2005/073367;    -   (b) a portion of the sequence in (a), which is enzymatically        equivalent to recombinant human arylsulfatase A    -   (c) an amino acid sequence analogue having at least 75% sequence        identity to any one of the sequences in (a) or (b) and at the        same time being enzymatically equivalent to recombinant human        arylsulfatase A.

It may be preferred that the degree of sequence identity between theenzyme produced according to the invention and SEQ ID NO: 3 of WO2005/073367 or SEQ ID NO: 4 of WO 2005/073367 is at least 80%, such asat least 85%, at least 90%, at least 95%, at least 97%, at least 98%, orat least 99%.

For the biological activity and the effects of the enzyme in vivorequires to be optimal it is an advantage if an adequate amount of theenzyme has acquired a glycosylation pattern as described above and hasbeen modified post translationally at position 51. Thus at least 50%,60%, 70%, 80%, 90%, 95% or 98% of the ASA of the present invention maybe in the above described glycoform/isoform.

The ASA of the present invention may in terms of its structure bedifferent from the rASA according to SEQ ID NO: 3 of 2005/073367. It maybe an advantage that the sequence of amino acid residues surrounding theCys-51 is identical or has a high degree of sequence identity to thecorresponding sequence in SEQ ID NO: 3. Thus, it may be preferred that alinear sequence of 20 amino acids, such as 19, 18, 17, 16, 15, 14, 13,12, 11, 10, 9, 8, 7, 6, 5 or 4 amino acid residues surrounding theCys-51 in the arylsulfatase A is identical or at least 90% identical,such as 95%, 96%, 97%, 98%, or 99% identical to the correspondingsequence in SEQ ID NO: 3 of 2005/073367. As the active form of rASAwithin the lysosymes is an octamer the ASA of the present invention mayin particular be a rASA which is an octamer or assembles into an octamerunder physiological conditions.

The enzyme activity of ASA, which is to be understood as the catalyticactivity of the rASA, may be measured in an enzyme assay based on therASA mediated hydrolysis of either a detectable substrate or asubstrate, which leads to a detectable end product. In a preferredaspect the assay is based on hydrolysis of the synthetic, chromogenicsubstrate, para-Nitrocatechol sulphate (pNCS) which has an end product,para-Nitrocatechol (pNC) that absorbs light at 515 nm.

Lysosomal Alpha-Mannosidase

In yet another embodiment the polypeptide of interest may be a lysosomalalpha-mannosidase (LAMAN). Lysomal alpha-mannosidase belongs to EC3.2.1.24 and is an exoglycosidase which hydrolyses the terminal,non-reducing alpha-D-mannose residues in alpha-D-mannosides from thenon-reducing end during the ordered degradation of N-linkedglycoproteins (Aronson and Kuranda FASEB J 3:2615-2622. 1989). In thecontext of the present invention the term lysosomal alpha-mannosidasemay be used interchangeably with the short term LAMAN.

The LAMAN of the present invention may in particular be of human origin.The human enzyme is synthesised as a single polypeptide of 1011 aminoacids with a putative signal peptide of 49 residues that is processedinto three main glycopeptides of 15, 42, and 70 kD (Nilssen et al. Hum.Mol. Genet. 6, 717-726. 1997).

The gene coding for LAMAN (MANB) is located at chromosome 19(19cen-q12), (Kaneda et al. Chromosoma 95:8-12. 1987). MANB consists of24 exons, spanning 21.5 kb (GenBank accession numbers U60885-U60899;Riise et al. Genomics 42:200-207. 1997). The LAMAN transcript is >>3,500nucleotides (nts) and contains an open reading frame encoding 1,011amino acids (GenBank U60266.1).

The cloning and sequencing of the human cDNA encoding LAMAN has beenpublished in three papers (Nilssen et al. Hum. Mol. Genet. 6, 717-726.1997; Liao et al. J. Biol. Chem. 271, 28348-28358. 1996; Nebes et al.Biochem. Biophys. Res. Commun. 200, 239-245. 1994). Curiously, the threesequences are not identical. When compared to the sequence of Nilssen etal (accession # U60266.1) a TA to AT change at positions 1670 and 1671resulting in a valine to aspartic acid substitution was found by Liao etal. and Nebes et al.

In a most preferred embodiment, the lysosomal alpha mannosidasecomprises the amino acid sequence of SEQ ID NO.: 1 of WO 2005/094874.

For practical and economical reasons it is preferred that the LAMAN ofthe present invention is produced recombinant. By recombinant productionit may also be possible to obtain a preparation of the enzyme wherein alarge fraction contains mannose-6-phosphate. Recombinant production maybe achieved after transfection of a cell using a nucleic acid sequencecomprising the sequence of SEQ ID NO: 2 of WO 2005/094874.

The alpha-mannosidase is preferably made in a mammalian cell system asthis will result in a glycosylation profile, which ensures efficientreceptor mediated uptake in cells of for instance visceral organs of thebody. In particular, it has been found that production of the enzyme inCHO, COS or BHK cells ensures adequate post-translational modificationof the enzyme by addition of mannose-6-phosphate residues. In addition acorrect sialylation profile is obtained. Correct sialylation is known tobe important in order to prevent uptake by the liver, because of exposedgalactose residues.

In even more preferred embodiments the mammalian cell system istherefore selected from the group comprising CHO, COS cells or BHK cells(Stein et al. J Biol Chem. 1989, 264, 1252-1259). It may further bepreferred that the mammalian cell system is a human fibroblast cellline.

In a most preferred embodiment, the mammalian cell system is a CHO cellline.

In another embodiment the lysosomal alpha-mannosidase may be apreparation of lysosomal alpha-mannosidase wherein a fraction of saidpreparation consists of lysosomal alpha mannosidase having one or moreN-linked oligosaccharides carrying mannose 6-phosphate groups.

It is further preferred that a fraction of a preparation of saidlysosomal alpha-mannosidase is capable of binding to mannose 6-phosphatereceptors.

The ability of the enzyme to bind to mannose-6-phosphate receptors maybe determined in an in vitro assay as described in example 1 of WO2005/094874. Here, binding of the enzyme to a MPR affinity 300 Matrixprovides a measure of its ability to bind to mannose-6-phosphatereceptors. In a preferred embodiment of the invention binding of theenzyme to mannose-6-phosphate receptors occurs in vitro.

In more preferred embodiments of the invention this fraction correspondsto from 1 to 75% of the activity of a preparation of lysosomalalpha-mannosidase, such as from 2 to 70%, such as from 5 to 60%, such asfrom 10 to 50% such as from 15 to 45%, such as from 20 to 40%, such asfrom 30 to 35%.

Accordingly, it is preferred that the lysosomal alpha-mannosidase has acontent of mannose 6-phosphate residues allowing mannose 6-phosphatedependent binding of from 2 to 100%, 5 to 95%, 10 to 90%, 20 to 80%, 30to 70% or 40 to 60% of the amount of enzyme to a Man-6-P-receptormatrix. At present, the degree of phosphorylation has been analysed inseveral batches of enzyme and, typically, from 30 to 45% of the enzymeis phosphorylated and binds the affinity matrix.

It is further preferred that a fraction constituting from 2-100%, 5-90%,10-80%, 20-75%, 30-70%, 35-65% or 40-60% of the amount of said lysosomalalpha-mannosidase binds to the Man-6-P-receptor with high affinity.Theoretically, two mannose 6-phosphate groups must be positioned closeto each other in order for the enzyme to bind a Man-6-P-receptor withhigh affinity. Recent observations suggest that the distance between thephosphorylated mannose residues must be 40 Å or less in order to obtainhigh affinity binding. In the human lysosomal alpha-mannosidaseaccording to SEQ ID NO: 1 of WO 2005/094874 the two mannose 6-phosphateresidues may be situated at the asparagines residues in positions 367and 766. Accordingly, it is preferred that the medicament according tothe present invention comprises lysosomal alpha-mannosidase, a fractionof which carries mannose 6-phosphate groups at both of these asparagineresidues.

Preferably, the alpha-mannosidase is made by recombinant techniques. Ina further embodiment, the alpha-mannosidase is of human origin (hLAMAN)and still more preferred a mature human alpha-mannosidase (mhLAMAN) or afragment thereof. The fragment may be modified, however the active sitesof the enzyme should be preserved.

It is to be expected that, in preparations of alpha-mannosidaseaccording to the present invention, one fraction of the enzyme isrepresented by its precursor form, while other fractions represent theproteolytically processed forms of approximately 55 and 70 kDa.

Galactocerebrosidase

In another embodiment the polypeptide of interest may be agalactocerebrosidase, which may be shortended to GALC.Galactocerebrosidase belongs to E.C. 3.1.6.46 and are enzymes capable ofcatalysing the reaction ofD-galactosyl-N-acylsphingosine+H2O=D-galactose+N-acylsphingosine, thusGALC catalyzes the degradation of galactolipids in for example myelin.

The GALC enzyme derived from humans is a glycosylated lysosomal enzymecomprising 643 amino acids and with a molecular weight of 72.8 kDa. TheGALC of the present invention may in particular be of human origin. In afurther embodiment the GALC may be expressed recombinant in one of thepreviously mentioned host cells. The host cell for recombinantexpression of GALC may in particular be a CHO cell.

In the description and in the claims reference is made to the followingamino acid and nucleic acid sequences:

Sequence Sequence description identifier PBGD coding sequence 1 SEQ IDNO.: 1 PBGD coding sequence 2 SEQ ID NO.: 2 PBGD coding sequence 3 SEQID NO.: 3 PBGD coding sequence 4 SEQ ID NO.: 4 PBGD coding sequence 5SEQ ID NO.: 5 PBGD coding sequence 6 SEQ ID NO.: 6 PBGD coding sequence7 SEQ ID NO.: 7 PBGD coding sequence 8 SEQ ID NO.: 8 PBGD codingsequence 9 SEQ ID NO.: 9 PBGD coding sequence 10 SEQ ID NO.: 10 PBGDcoding sequence, GenBank Acc. No. X04217 SEQ ID NO.: 11 PBGD codingsequence, GenBank Acc. No. X04808 SEQ ID NO.: 12 PBGD coding sequence,GenBank Acc. No. M95623 SEQ ID NO.: 13 PBGD aa sequence from codingsequence, GenBank SEQ ID NO.: 14 Acc. No. M95623, Constitutive form PBGDaa sequence from coding sequence, GenBank SEQ ID NO.: 15 Acc. No.M95623, Erythropoietic form ASA coding sequence Genbank Acc. No. J04593SEQ ID NO.: 16 ASA coding sequence SEQ ID NO.: 1 of WO SEQ ID NO.: 172005/073367 ASA aa sequence SEQ ID NO.: 2 of WO 2005/073367 SEQ ID NO.:18 ASA aa sequence SEQ ID NO.: 3 of WO 2005/073367 SEQ ID NO.: 19 ASA aasequence SEQ ID NO.: 4 of WO 2005/073367 SEQ ID NO.: 20 LAMAN aasequence SEQ ID NO.: 1 of WO SEQ ID NO.: 21 2005/094874 LAMAN codingsequence SEQ ID NO.: 1 of WO SEQ ID NO.: 22 2005/094874Galactocerebrosidase coding sequence SEQ ID NO.: 23 Galactocerebrosidaseaa sequence SEQ ID NO.: 24

With reference to these sequences the polypeptide of interest, accordingto preferred embodiments of the invention, comprises an amino acidselected from the group consisting of:

-   -   i) an amino acid sequence as defined by any of SEQ ID NO.s: 14,        15, 18, 19, 20, 21 and 24;    -   ii) a functionally equivalent part of an amino acid sequence as        defined in i); and    -   iii) a functionally equivalent analogue of an amino acid        sequence as defined in i) or ii), the amino acid sequence of        said analogue being at least 75% identical to an amino acid        sequence as defined in i) or ii).

In particular embodiments the analogue in iii) is at least 80% identicalto a sequence as defined in i) or ii), such as at least 85%, at least90%, at least 95%, at least 98%, at least 99%, or such as at least 99.5%identical to a sequence as defined in i) or ii).

Further, the polypeptide of interest may be obtained by recombinantexpression using a nucleic acid sequence comprising a sequence selectedfrom the group consisting of:

-   -   i) a nucleic acid sequence as defined by any of SEQ ID NO.s:        1-13, 16, 17, 22 and 23;    -   ii) a nucleic acid sequence which is at least 75% identical to a        nucleic acid sequence as defined in i).

For recombinant production of the polypeptide it may further bepreferred that the acid sequence in ii) is at least 80% identical to asequence as defined in i), such as at least 85%, at least 90%, at least95%, at least 98%, at least 99%, or such as at least 99.5% identical toa sequence as defined in i).

Composition Comprising a Polypeptide of Interest

The following description of a composition comprising a polypeptide ofinterest relates both to a composition comprising a polypeptide which isconcentrated according to a method of the present invention and it alsorelates to a composition of the present invention comprising at least 10mg/ml polypeptide of interest.

The present invention also relates to a composition comprising at least10 mg/ml polypeptide of interest, wherein the polypeptide of interestmay be any polypeptide according to the present invention, such as inparticular rhPBGD, aryl sulfatase, alpha-mannosidase orgalactocerebrosidase. Said composition may in particular comprise atleast 25 mg/ml polypeptide of interest, such as at least 50 mg/ml or atleast 75 mg/ml or at least 100 mg/ml polypeptide of interest. Thus saidcomposition may in particular comprise between 10-1000 mg/ml polypeptideof interest, such as between 10-500 mg/ml or between 10-300 mg/ml orbetween 10-200 mg/ml or between 25-500 mg/ml or between 25-400 mg/ml orbetween 40-400 mg/ml or between 40-300 mg/ml or between 50-400 mg/ml orbetween 50-300 mg/ml or between 75-400 mg/ml or between 75-300 mg/ml orbetween 100-200 mg/ml or between 100-150 mg/ml polypeptide of interest.

The composition comprising a polypeptide of interest may in particularbe an aqueous solution.

Besides comprising a high concentration of polypeptide of interest saidcomposition may in particular further comprise no aggregates of thepolypeptide of interest or at least only very few aggregates. Hence theamount of polypeptide of interest present as aggregates may inparticular constitute less than 5 w/w % of the total amount ofpolypeptide of interest in the composition. In particular saidaggregates may constitute less than 4 w/w %, such as less than 3 w/w %,or less than 2 w/w %, or less than 1 w/w %, or less than 0.5 w/w %, orless than 0.1 w/w % of the total amount of polypeptide of interest. Inthe present context the term “aggregates” means any form of thepolypeptide of interest which is not monomeric. Thus the termencompasses any dimer or multimer of the polypeptide of interest.

Furthermore, it is an advantage if said composition comprises only thepolypeptide of interest or at least only minor traces of other proteins,i.e. proteins different from polypeptide of interest. Hence in aparticular embodiment said composition comprises less than 1 w/w %, suchas less than 0.5 w/w %, or less than 0.1 w/w %, or less than 0.05 w/w %,or less than 0.01 w/w % other proteins than the polypeptide of interest.

A range of factors affect the stability and activity of polypeptides andthe composition comprising a polypeptide of interest may therefore inparticular be optimized to keep the polypeptide of interest as stable aspossible.

The pH generally affects the stability of a polypeptide of interest,thus the pH of a composition comprising a polypeptide of interest may inparticular be in the range of 7.5-8.5, such as in particular between pH7.7-8.2, more particularly between pH 7.8-8.0 or between pH 7.85-7.95,such as pH 7.8 or pH 7.9. This may in particular be the case if thepolypeptide of interest is PBGD.

Thus the composition comprising a polypeptide of interest may inparticular comprise a buffer capable of keeping the composition withinthe described pH range. Examples of such buffers include but are notlimited to TRIS-HCL, Na-Citrate and Na₂HPO₄. The concentration of such abuffer may depend on the choice of the particular buffer and thepresence of other components in the composition. If the buffer isNa₂HPO₄ the concentration of Na₂HPO₄ may be in the range of 0.5-15 mM,such as in the range of 1-10 mM, or in the range of 1.5-7.5 mM, such asin the range of 1.83-7.4 mM, or in the range of 1.5-3 mM, such as in therange of 1.83-3.7 mM, or in the range of 1.83-2.45 mM, or in the rangeof 3.5-7.5 mM, such as in the range of 3.6-7.4 mM, or in the range of5.4-7.4 mM, such as 1.84 mM, or 2.45 mM, or 3.67 mM or 5.51 mM or 7.34mM.

If the buffer is TRIS-HCL the concentration of TRIS-HCL may inparticular be in the range of 2-50 mM, such as 2-40 mM, or 2-30 mM, or2-20 mM, or 2-10 mM, or 5-25 mM, or 5-20 mM, or 8-12 mM, or 9-11 mM,e.g. 10 mM.

Examples of other compounds which the composition comprising apolypeptide of interest may comprise include but are not limited toamino acids, sugars, alcohols and detergents. Examples of such suitablecompounds include but are not limited to glycine, mannitol, sucrose,L-serine, Tween 80 or a combination of one or more of said compounds.The concentration of these compounds depend on the particular compound,but for glycine the concentration may in particular be in the range of1-200 mM, such as in the range of 5-190 mM, or in the range of 10-180mM, or in the range of 10-170 mM, or in the range of 20-160 mM, or inthe range of 20-150 mM, or in the range of 25-125 mM, or in the range of5-100 mM, or in the range of 5-90 mM, or in the range of 5-80 mM, or inthe range of 5-70 mM, or in the range of 5-60 mM, or in the range of10-100 mM, or in the range of 10-90 mM, or in the range of 10-80 mM, orin the range of 10-70 mM, or in the range of 10-60 mM, or in the rangeof 12-60 mM, or in the range of 12-55 mM, or in the range of 13.5-54 mM,or in the range of 10-30 mM, such as in the range of 13.5-27 mM, or inthe range of 13.5-18 mM, or in the range of 25-55 mM, such as in therange of 27-54 mM, or in the range of 40-55, such as in the range of40.5-54 mM, such as 12.5, 13, 13.5, 14, 14.5, 17, 17.5, 18, 18.5, 19,25, 26, 27, 28, 29, 30, 39.5, 40, 40.5, 41, 41.5, or 53, 53.5, 53, 54.5or 55 mM.

The concentration of mannitol may in particular be in the range of50-1000 mM, such as in the range of 50-900 mM, or in the range of 50-800mM, or in the range of 50-700 mM, or in the range of 50-600 mM, or inthe range of 100-900 mM, or in the range of 100-800 mM, or in the rangeof 100-700 mM, or in the range of 100-600 mM, or in the range of 100-500mM, or in the range of 120-525 mM, or in the range of 125-500 mM, or inthe range of 100-300 mM, such as in the range of 120-275 mM, or in therange of 120-170 mM, or in the range of 200-600 mM, such as in the rangeof 225-550 mM, or in the range of 240-510 mM, or in the range of 370-525mM, such as 120, 125, 130, 160, 165, 166.7, 170, 175, 200, 221, 225,250, 275, 300, 365, 370, 375, 380, 385, 490, 495, 500, 505 or 510 mM.

The concentration of sucrose may in particular be in the range of 1-200mM, such as in the range of 5-190 mM, or in the range of 10-180 mM, orin the range of 10-170 mM, or in the range of 20-160 mM, or in the rangeof 20-150 mM, or in the range of 25-125 mM, or in the range of 5-100 mM,or in the range of 5-90 mM, or in the range of 5-80 mM, or in the rangeof 5-70 mM, or in the range of 5-60 mM, or in the range of 10-100 mM, orin the range of 10-90 mM, or in the range of 10-80 mM, or in the rangeof 10-70 mM, or in the range of 10-60 mM, or in the range of 12-60 mM,or in the range of 12-55 mM, or in the range of 13.5-54 mM, or in therange of 10-30 mM, such as in the range of 13.5-27 mM, or in the rangeof 13.5-18 mM, or in the range of 25-55 mM, such as in the range of27-54 mM, or in the range of 40-55, such as in the range of 40.5-54 mM,such as 12.5, 13, 13.5, 14, 14.5, 17, 17.5, 18, 18.5, 19, 25, 26, 27,28, 29, 30, 39.5, 40, 40.5, 41, 41.5, or 53, 53.5, 53, 54.5 or 55 mM. Ifsucrose is included in a composition which also comprises mannitol theconcentration of mannitol may in particular be lowered corresponding tothe concentration of sucrose; i.e. the concentration of mannitol andsucrose together may in particular be the same as the concentration ofmannitol if this was to be used alone.

The concentration of Tween 80 may in particular be in the range of0.001-1 w/v %, such as in the range of 0.005-1 w/v %, or in the range of0.01-1 w/v %, or in the range of 0.001-0.5 w/v %, or in the range of0.005-0.5 w/v %, or in the range of 0.01-0.5 w/v %, or in the range of0.05-0.4 w/v %, or in the range of 0.05-0.3 w/v %, or in the range of0.05-0.2 w/v %, or in the range of 0.075-0.4 w/v %, or in the range of0.075-0.3 w/v %, or in the range of 0.075-0.2 w/v %, or in the range of0.09-0.2 w/v %, such as 0.075, 0.08, 0.09, 0.1, 0.125, 0.15, 0.175 or0.2 w/v %.

The composition comprising a polypeptide of interest, wherein thepolypeptide in particular may be a PBGD, an aryl sulfatase, a lysosomalalpha-mannosidase or a galactocerebrosidase, may in particular comprisea combination of one or more of the above-mentioned compounds. Asuitable example of such a composition may be one which besides thepolypeptide of interest comprises Na₂HPO₄, glycine and mannitol. The pHof the composition and the concentration of the different compounds maybe as described above. Hence said composition may in one embodimentcomprise 0.5-15 mM Na₂HPO₄, 1-200 mM glycine, 50-1000 mM mannitol and apH in the range of 7.5-8.5. Any combination of the above mentionedconcentrations of compounds and pH are encompassed by the presentinvention. A specific example of a suitable combination of othercompounds and pH in the composition comprising a polypeptide of interestis one which comprises 3.67 mM Na₂HPO₄, 27 mM glycine, 250 mM mannitoland has a pH in the range of 7.7 to 7.9.

Other examples of suitable compositions include, but are not limited toany of the following:

-   -   1.84 mM Na₂HPO₄, 13.5 mM glycine, 125 mM mannitol and pH in the        range of 7.7 to 7.9.    -   2.45 mM Na₂HPO₄, 18 mM glycine, 167 mM mannitol and pH in the        range of 7.7 to 7.9.    -   5.51 mM Na₂HPO₄, 40.5 mM glycine, 375 mM mannitol and pH in the        range of 7.7 to 7.9.    -   7.34 mM Na₂HPO₄, 54 mM glycine, 500 mM mannitol and pH in the        range of 7.7 to 7.9.    -   3.67 mM Na₂HPO₄, 27 mM glycine, 220 mM mannitol, 30 mM sucrose        and pH in the range of 7.7 to 7.9.    -   3.67 mM Na₂HPO₄, 245 mM mannitol, 32 mM sucrose and pH in the        range of 7.7 to 7.9.    -   3.67 mM Na₂HPO₄, 27 mM L-serine, 250 mM mannitol and pH in the        range of 7.7 to 7.9.    -   10 mM TRIS-HCl, 27 mM glycine, 250 mM mannitol and pH in the        range of 7.7 to 7.9.    -   3.67 mM NaCitrat, 27 mM glycine, 250 mM mannitol and pH in the        range of 7.7 to 7.9.    -   3.67 mM Na₂HPO₄, 27 mM glycine, 220 mM mannitol, 29 mM sucrose,        0.1% (w/v) Tween 80 and pH in the range of 7.7 to 7.9.    -   3.67 mM Na₂HPO₄, 27 mM glycine, 220 mM mannitol, 29 mM sucrose,        0.1% (w/v) Tween 80 and pH in the range of 7.7 to 7.9.

The composition comprising a polypeptide of interest may in particularbe used for therapeutic applications in mammals. Thus the compositioncomprising a polypeptide of interest may in particular be isotonic withregard to the tissue of mammals, e.g. it may in particular have anosmolality in the range of 200-400 mOsm/kg, such as in the range of250-350 mOsm/kg or in the range of 275-325 mOsm/kg or in the range of295-305 mOsm/kg, such as 295 mOsm/kg or 300 mOsm/kg or 305 mOsm/kg.

Method of Concentrating a Polypeptide of Interest

The method of the present invention comprises the steps of a)centrifugation and/or filtration of a composition comprising apolypeptide of interest and b) concentrating the composition from stepa). The inventors of the present invention have found that bycentrifugation and/or filtrating a composition comprising a polypeptideof interest prior to concentrating said composition it is possible toobtain a composition comprising a highly concentrated polypeptide ofinterest without any or with at least only few aggregates of thepolypeptide of interest. Furthermore, it is generally an advantage fortherapeutic applications of a polypeptide that the amount of polypeptideaggregates is reduced, e.g. as they may increase the risk of elicitingan immune response towards the polypeptide.

For administration of a polypeptide subcutaneously it is an advantagethat the polypeptide composition has a high activity in a small volumeas only small volumes can be injected subcutaneously.

Proteins or polypeptides may in general form aggregates when they areconcentrated. Thus it is an advantage that when the method of thepresent invention is used to concentrate a polypeptide of interest itdoes not cause a high rate of polypeptide aggregate formation. As shownin the examples the amount of PBGD aggregates in the compositionobtained by the concentration method of the present invention is similarto that of a non-concentrated PBGD composition.

In a particular embodiment step a) of the method is performed prior tostep b).

Step a) Centrifugation and/or Filtration

The inventors of the present invention have found that prior toconcentrating a composition comprising a polypeptide of interest it isan advantage to pre-treat the composition by centrifugation and/orfiltration of the composition as by this pre-treatment many or most ofthe polypeptide aggregates are removed.

When the concentration of the composition in step b) is performed by amethod which relies on the use of a filter or membrane, such asultrafiltration, the presence of aggregates may block the filter ormembrane so that small molecules and liquid are not able to cross thefilter or membrane. This may decrease the speed by which the compositionis concentrated and/or completely block any further concentration.

Hence for this type of concentration the pre-treatment according to stepa) is an advantage as removal of the aggregates makes it possible toobtain compositions of a polypeptide of interest which are moreconcentrated than if said composition were not been pre-treated.

When the concentration of the composition in step b) is performed by amethod which is based on the removal of water, such as freeze-drying orevaporation, the pre-treatment in step a) has the advantage that itreduces the amount of aggregates present in the concentratedcomposition.

Step a) may be performed by one of the following three alternatives:

-   -   Centrifugation,    -   Filtration, or    -   Centrifugation and filtration.

If step a) comprises both centrifugation and filtration it is anadvantage to perform the centrifugation prior to the filtration as theinventors of the present invention have found that the centrifugationremoves most of large aggregates and the filtration subsequently removesthe remaining smaller aggregates.

Centrifugation

To be able to remove the aggregates the composition comprising apolypeptide of interest may be centrifuged at a force in the range of1500-3000 g, such as in the range of 1800-2500 g, or in the range of2000-2300 g.

Typically the composition may be centrifuged for 10-60 minutes, such asfor 15-50 minutes or for 20-40 minutes.

As the temperature may affect the stability of the polypeptide ofinterest the centrifugation may be performed at a temperature in therange of 2-20° C., such as from 3-15° C. or in the range of 3-10° C., orin the range of 3-8° C., such as at 4° C. or 5° C. or 6° C.

The centrifugation results in that the polypeptide of interestaggregates sediment, i.e. they form a pellet, while the individualpolypeptide of interest molecules stays in the solution. So it is thesupernatant of the centrifuged composition which is subsequently used inthe method of the present invention.

Filtration

The composition comprising a polypeptide of interest may be filteredthrough a filter having a pore-size in the range of 0.20-5 μm, such asin the range of 0.2-2.5 μm.

Besides the pore-size of the filter also the material of which thefilter is made of may affect filtration of polypeptide of interest.Examples of suitable membrane filters include but are not limited topolyethersulfone (PES), cellulose acetate, regenerated cellulose andpolyvinylidene fluoride (PVDF).

When molecules such as proteins are filtered it is usually the smallmolecules which are removed thus after filtration the polypeptide ofinterest may generally be present in the retentate. Hence it isgenerally the retentate from the filtration which is used in thesubsequent steps of the present invention.

Step b) Concentrating

In principle any method of concentrating the polypeptide of interestcomposition may be used in step b) of the present invention.

Examples of such suitable methods include but are not limited toultrafiltration and concentration by removal of water.

Ultrafiltration

Ultrafiltration is a separation method in which hydraulic pressure isused to force molecules and solvent across a membrane comprising poresof a particular size, also known as the cut-off size of value. Onlymolecules which have a molecular weight smaller than the cut-off valueof the membrane are able to cross the membrane while those with a largermolecular weight do not cross the membrane and form the so calledretentate. The molecules present in the retentate are therebyconcentrated as the solvent flows across the membrane.

In a particular embodiment the concentration of the solution orcomposition comprising a polypeptide of interest may be performed byTangential flow filtration (TFF). This method is in particular usefulfor large-scale concentration, i.e. for concentration of solutions witha volume from one liter to several hundreds of liters. Thus this methodis in particular useful for production of concentrated solutions of apolypeptide of interests on an industrial scale.

The TFF technique is based on the use of a particular apparatus whichcauses the solution which is to be filtrated to flow across asemi-permeable membrane; only molecules which are smaller than themembrane pores will pass through the membrane, forming the filtrate,leaving larger matter to be collected (retentate). With the TFF methodtwo different pressures are applied; one to pump the solution into thesystem and to circulate it in the system (inlet pressure), and anotherpressure is applied over the membrane (membrane pressure) to force thesmall molecules and the solvent across the membrane. The inlet pressuremay typically be in the range of 1-3 bar, such as between 1.5-2 bar. Themembrane pressure may typically be larger than 1 bar.

The concentrated composition of a polypeptide of interest may becollected as the retentate when TFF is used to concentrate thecomposition.

Membranes useful for TFF may typically be made of regenerated celluloseor polyethersolufone (PES).

The pore-size of the membrane may typically have a molecular weightcut-off which is smaller than 10.000 Mw, such as in the range of10-10.000 Mw.

In another embodiment the concentration of the composition comprising apolypeptide of interest may be performed by the use of a centrifugaldevice. The principle of this method is that the solution is filtratedover a membrane by the application of a centrifugal force over themembrane. Such membranes are often characterized by a molecular weight(Mw) cut-off, i.e. this is the maximum molecular size of compounds whichare able to cross the membrane and compound with a molecular size largerthan this will not cross the membrane. The Mw cut-off of the membranesused in the present invention may in particular be smaller than 30.000Mw, such as between 10-30.000 Mw.

The membrane may in particular be made of polyethersulfone (PES) orregenerated cellulose.

Examples of such suitable commercial filter devices may be CentriconPlus-80 or Centricon Plus-15.

The concentration may typically be performed by centrifugation at2000-4500 g, such as between 2500-4000 g, or between 2750-3500 g, orbetween 3000-3500 g, such as at 3000 g or 3100 g or 3200 g or 3300 g or3400 g or 3500 g.

Typically the centrifugation may be run for several hours, e.g. for morethan one hour, such as for 1-10 hours.

To minimize any negative effects on the stability of the polypeptide ofinterest the centrifugation may in particular be performed at atemperature in the range of 2-20° C., such as in the range of 3-15° C.or in the range of 3-10° C. or in the range of 3-6° C.

Concentrating by Removal of Water

The principle of concentration by removal of water is usually that all,or most, of the water is removed to obtain a solid, and thensubsequently diluting or dissolving this solid in a volume of waterwhich is less than what it was previously diluted or dissolved in.However, it may in principle be performed by just removing the necessaryamount of water to obtain the desired concentration without subsequentlyre-diluting or re-dissolving the compound.

Examples of suitable methods of concentrating by removal of waterinclude freeze-drying and evaporation.

Both for freeze-drying and evaporation the three most relevantparameters is the temperature, pressure and the time.

The method of freeze-drying may be comprise the following three or foursteps; a freezing-phase, a primary drying phase and a secondary dryingphase and optionally a step of annealing after the freezing phase.Freeze-drying may in particular be performed as described with regard tofreeze-drying included as a further step of the method of the presentinvention.

Further Steps

The polypeptide of interest may derive from a natural source, i.e. fromcells naturally expressing the polypeptide of interest, or it may inparticular be expressed recombinant.

Independent of where the polypeptide of interest derives from it mayhave been purified before being subjected to a method of the presentinvention.

Such “purification” may in particular include but is not limited toremoval of cell debris, removal of other proteins than polypeptide ofinterest and removal of other components which may be present in thesource from which the polypeptide of interest is derived. Thus in aparticular embodiment of the present invention the compositioncomprising a polypeptide of interest comprises less than 5 w/w %, orless than 1 w/w % or less 0.5 w/w % or less than 0.1 w/w % or less than0.05 w/w % or less than 0.01 w/w % other proteins than the polypeptideof interest.

Thus other proteins which are expressed by e.g. a host cell may beremoved from the composition comprising a polypeptide of interest beforeit is used in a method of the present invention.

Thus in a particular embodiment the method of the present invention maycomprise one or more of following steps prior to step a):

-   -   i) recombinant expression of a polypeptide of interest    -   ii) purification of polypeptide of interest composition by one        or more steps of chromatography    -   iii) exchange of the formulation buffer

Recombinant expression of a polypeptide of interest may in particular beperformed as described previously with regard to the polypeptide ofinterest.

If the polypeptide of interest is PBGD examples of suitable types ofchromatography include but are not limited to affinity chromatography,Ion Exchange Chromatography (IEC) and chromatography on a hydroxyapatitecolumn. In principle any combination of these chromatography methods maybe used. The inventors of the present invention have previously foundfor PBGD that it is an advantage to perform at least the step ofaffinity chromatography and if this is combined with any of the othermethods of chromatography it is an advantage to perform the step ofaffinity chromatography prior to the other chromatography steps (seee.g. WO 03/002731).

For the embodiment where the polypeptide of interest is PBGD examples ofcommercially available affinity chromatography columns include affinitycoupling, group specific affinity, and metal chelate affinity columns.

The product catalogue 2001 of the company Amersham Pharmacia Biotechgives examples of affinity coupling columns such as columns comprisingimmobilising ligands containing —NH₂ and columns comprising ligandscontaining primary amino groups.

Metal chelate affinity columns are specially preferred for purifyingproteins via metal ion complex formation with exposed histidine groups.Example 3 of WO01/07065 describes construction of a recombinant humanPorphobilinogen deaminase with a “His-Tag” (rhPBGD-His). In order topurify rhPBGD-His it is preferred to use a metal chelate affinitycolumn, such as a column having a cobalt metal affinity resin.

Examples of other suitable methods of affinity chromatography includebut are not limited to columns having porcine heparin as ligand orcolumns having 1-Amino-4-[[4-[[4-chloro-6-[[3 (or4)-sulfophenyl]amino]-1,3,5-triazin-2-yl]amino]-3-sulfophenyl]amino]-9,10-dihydro-9,10-dioxo-2-anthracenesulfonicacid, also known as Cibracon Blue 3G, as ligand and using Triazinecoupling as the ligand coupling method. A commercially available exampleof the latter is Blue Sepharose 6 Fast Flow (FF) from Amersham PharmaciaBiotech. Accordingly, a preferred embodiment of the invention relates tothe process, as described herein, wherein the affinity chromatographycolumn of step (i) is a column using a triazine coupling as ligandcoupling method, and more preferably wherein the ligand is Cibacron Blue3G.

The term “Ion Exchange Chromatography (IEC)” should herein be understoodaccording to the art as a column separating molecules such as proteinson the basis of their net charge at a certain pH by electrostaticbinding to a charged group on the column. Ion exchange denotes theabsorption of ions of one type onto a column in exchange for otherswhich are lost into solution.

Examples of suitable IEC columns are columns such as a Q Sepharosecolumn, a Q SP Sepharose column, or a CM Sepharose column, it may inparticular be a DEAE Sepharose column.

An example of a suitable hydroxyapatite column is a ceramichydroxyapatite column. Hydroxyapatite (Ca₅(PO₄)₃OH)₂ is a form ofcalcium phosphate that can be used for the separation and purificationof proteins, enzymes, nucleic acids, viruses, and other macromolecules.Ceramic hydroxyapatite is a spherical, macroporous form ofhydroxyapatite. CHT Type I (Bio-Rad) is an example of a suitablecommercially available ceramic hydroxyapatite chromatography column.

In one embodiment the method of the present invention may comprise thefollowing steps prior to step a):

-   -   i) recombinant expression of PBGD    -   ii) subjecting the PBGD composition from step i) to affinity        chromatography    -   iii) subjecting the PBGD composition of step ii) to ion exchange        chromatography

In a further embodiment the method of the present invention may comprisethe following steps prior to step a):

-   -   i) recombinant expression of PBGD    -   ii) subjecting the PBGD composition from step i) to affinity        chromatography    -   iii) subjecting the PBGD composition from step ii) to ion        exchange chromatography    -   iv) subjecting the PBGD composition from step iii) to a        hydroxyapatite column

Both of these methods may optionally include a further step of dilutionof diafiltration of the PBGD composition obtained from step ii). Thussaid step should be after step ii) and before iii), i.e. a step iia).Step iia) has the purpose of reducing the concentration of salts tosuitable conductivity, e.g. <10 mS/cm. This may in particular berelevant if DEAE Sepharose is used as resin in the ion exchangechromatography step, i.e. step iii), as this may facilitate binding ofthe captured PBGD to the DEAE Sepharose resin. Dilution may be obtainedby addition of purified water directly or by ultrafiltration againstpurified water.

The recombinant expression of PBGD, step 1) may be performed by any ofthe methods described above.

Examples of suitable affinity chromatography columns in step ii) may beany of the above mentioned.

Examples of suitable methods of performing ion exchange chromatographyin step iii) may be any of the above mentioned.

Examples of suitable hydroxyapatite chromatography columns in step iv)may be any of the above mentioned.

In a particular embodiment the affinity chromatography column may be acolumn using a triazine coupling as ligand coupling method, and inparticular such a method wherein the ligand is Cibracon Blue 3G. Thismay in particular be a Blue Sepharose 6 Fast Flow column, and the ionexchange chromatography column may be DEAE Sepharose column, and in theembodiment wherein the method also comprises a step iv) this column mayin particular be a ceramic hydroxyapatite column.

The method of the present invention may also comprise further stepsafter step b) of the method. Such steps include but are not limited toone or more of the following:

-   -   freeze-drying the composition comprising a concentrated        polypeptide of interest,    -   changing the buffer of the composition comprising a concentrated        polypeptide of interest,    -   sterile filtration of the composition comprising a concentrated        polypeptide of interest    -   evaporation

Different freeze-driers, volume of solutions to be freeze-dried andother parameters may be used in the method of the present invention. Anexample of a suitable freeze-dryer includes but is not limited to aLyostar (FTM-systems) freeze-drier as used the examples of the presentinvention, where the solutions comprising a concentrated polypeptide ofinterest, i.e. in this case PBGD, were filled in 2 and 6 ml injectionglass vials (type 1) and stoppered with rubber stoppers (chlorobutyl).The freeze-drying may be performed by the following three steps;

-   -   i) freezing,    -   ii) primary drying, and    -   iii) secondary drying.

Step i) freezing may in particular be performed by first loading asample in ambient temperature and cooling it to 0° C. and keeping it at0° C. for 30 minutes, before lowering the temperature by 1° C. perminute to −40° C. and keeping it at −40° C. for 30 minutes.

Step ii) primary drying may in particular be performed by drawing thevacuum pressure 126 mTorr, raising the temperature by 1° C. per minuteto 0° C. and keeping the sample at 0° C. for 360 minutes

Step iii) secondary drying may in particular be performed by drawing thefull vacuum simultaneously with raising the temperature by 0.5° C. perminute to +30° C. and keeping the sample at +30° C. for 360 minutes.

After the secondary drying the sample may further be closed under vacuumor closed after filling with nitrogen.

An example of a suitable freeze-drying method includes the one describedin the examples of the present invention.

The freeze-drying may in further embodiment comprise an annealing stepprior to the primary drying phase. The inventors of the presentinvention have found that inclusion of an annealing step in thefreeze-drying method improves the visual appearance, as visualised byfewer cracks, and/or results in a shorter reconstitution time of thefreeze-dried product compared to when the same method of freeze-dryingis used but without the annealing step. It is an advantage that the timefor reconstitution of a freeze-dried product is reduced, especially ifit is to be used as a pharmaceutical which is administered as asolution. An improved visual appearance is usually also regarded as anadvantage for most products.

Thus the freeze-drying may comprise the following steps:

-   -   i) freezing    -   ii) annealing    -   iii) primary drying    -   iv) secondary drying.

The freezing, primary drying and secondary drying steps may inparticular be performed as described above. The annealing step, i.e.step ii) may in particular be performed by after 30 minutes of freezing,raising the temperature at e.g. a rate of 2° C. per minute to −10° C. or−20° C. and keeping this temperature for 120 or 420 minutes and thenlowering the temperature e.g. a rate of 2° C. per minute to −40° C. atwhich temperature the sample may be kept at 60-90 minutes before startof the step of primary drying.

Changing the buffer of the composition comprising a concentratedpolypeptide of interest may in particular be performed by a) diluting,e.g. 5-15 times, the composition comprising a concentrated polypeptideof interest in a buffer or formulation, b) concentrating the dilutedcomposition again and performing the steps a) and b) a sufficient numberof times so that amount of the excipients in the buffer or formulationpresent in the composition before these steps constitute less than e.g 5v/v % or less than 1 v/v % of excipients in the buffer or formulationpresent in said composition after said steps were performed.

In particular the composition comprising a polypeptide of interestobtained from step b) of the present invention may in particular furthercomprise a step of sterile filtration of said composition and/or a stepof freeze-drying the composition.

Sterile filtration is generally performed by filtration of thecomposition through a filter with a pore-size of 0.22 μm or 0.20 μm.Freeze-drying may in particular be performed as described above.

The present invention also relates to a freeze-dried compositionobtained by a method of the present invention.

Subcutaneous Injection

The present invention also relates to the use of a compositioncomprising in the range of 50-300 mg/ml polypeptide of interest for themanufacture of a medicament for subcutaneous injection into a mammal.

The polypeptide of interest may be any polypeptide of interest accordingto the present invention, including but not limited to PBGD, arylsulfatase A, lysosomal alpha-mannosidase and galactocerebrosidase.

The term subcutaneous is often shortened to s.c. and the two terms maybe used interchangeably in the context of the present invention.

When injection is performed subcutaneously it is usually not possible toinject more than 1.5 mL due to physiologically restraints.

As the patient usually needs a certain amount of the particularpolypeptide of interest there is a correlation between the volume of thecomposition comprising a polypeptide of interest which needs to beadministered to the patient and of the concentration of polypeptide ofinterest in said composition.

It is therefore an advantage of the present invention that thecomposition comprising a polypeptide of interest comprises a highconcentration of the polypeptide of interest and that this highconcentration of the polypeptide of interest can be obtained without theformation of large amounts of polypeptide aggregates. The use of suchconcentrated polypeptide of interest compositions makes it possible toinject a smaller volume of said composition and at the same time ensurethat the patient receives an adequate amount of the polypeptide ofinterest; thus making it easier to administer the polypeptide ofinterest subcutaneously.

The above-mentioned composition comprising a polypeptide of interest mayin particular comprise between 75-250 mg/ml, such as between 75-200mg/ml or between 75-150 mg/ml or between 100-150 mg/ml or between100-125 mg/ml or between 125-150 mg/ml of polypeptide of interest.

As described above the volume of composition comprising a polypeptide ofinterest which it is necessary to inject into the patient to ensure thatthe patient receives an adequate amount of the polypeptide of interestcorrelates with the concentration of the polypeptide of interest in saidcomposition.

Thus the volume of such a composition will generally be adjustedaccording to the concentration of the polypeptide of interest in thecomposition. However, the volume may generally be in the range of0.1-1.5 ml, such as in the range of 0.1-1.5 ml or in the range of0.5-1.5 ml or in the range of 0.5-1.5 ml or in the range of 0.75-1.5 mlor in the range of 0.75-1.5 ml or in the range of 1-1.5 ml or in therange of 1-1.5 ml.

The amount of polypeptide of interest which it is relevant to administerto a patient generally depends on the weight of the individual and theparticular polypeptide of interest.

In one embodiment the present invention relates to a method of treatinga mammal for Acute Intermittent Porphyria comprising subcutaneousinjection of a composition of 50-300 mg/ml PBGD.

Administration of PBGD may in particular be useful for the treatment ofAcute Intermittent Porphyria. However, it is contemplated thatadministration of PBGD also may be useful for the treatment of otherporphyrias, such as Hereditary coproporphyria or Variegata porphyria.Porphyria is a term used to collectively describe a number of diseasescaused by different deficiencies in the heme biosynthetic pathway. Henceit is contemplated that administration of PBGD, e.g. in combination withother therapeutics, to a patient suffering from any type of porphyriamay help to increase the overall turnover of the different intermediatesin the pathway. For example Meissner P N et al., 1986, European Journalof Clinical Investigation, vol. 16, 257-261; Hift R J et al., 1997, S.Afr. Med. J., vol. 87, 718-27 and Meissner P et al., 1993, J. Clin.Invest., vol. 91, 1436-44 describe accumulation of ALA and PBG inHereditary coproporhyria and Variegata porphyria. In theses diseases theaccumulation of ALA and PBG results from enzymatic defects that arelocated four and five steps downstream form the conversion of ALA toPBG, respectively. In the two most recent papers it is described how theporphyrinogen which accumulates in patients with Variegata porphyria iscapable of inhibiting PBG-deaminase.

In a further embodiment the present invention relates to a method oftreating a mammal for metachromatic leukodystrophy comprisingsubcutaneous injection of a composition of 50-300 mg/ml aryl sulfataseA.

Metachromatic leukodystrophy (MLD) is caused by an autosomal recessivegenetic defect in the lysosomal enzyme Arylsulfatase A (ASA), resultingin a progressive breakdown of membranes of the myelin sheath(demyelination) and accumulation of galactosyl sulphatide (cerebrosidesulphate) in the white matter of both the central nervous system (CNS)and the peripheral nervous system. In histologic preparations,galactosyl sulphatide forms spherical granular masses that stainmetachromatically. Galactosyl sulphatide also accumulates within thekidney, gallbladder, and certain other visceral organs and is excretedin excessive amounts in the urine.

Galactosyl sulfatide is normally metabolised by the hydrolysis of3-O-sulphate linkage to form galactocerebroside through the combinedaction of the lysosomal enzyme arylsulfatase A (EC 3.1.6.8) (Austin etal. Biochem J. 1964, 93, 15C-17C) and a sphingolipid activator proteincalled saposin B. A profound deficiency of arylsulfatase A occurs in alltissues from patients with the late infantile, juvenile, and adult formsof MLD (see below). In the following, the arylsulfatase A protein willbe termed “ASA”. A profound deficiency of ASA occurs in all tissues frompatients with MLD.

In yet another embodiment the present invention relates to a method oftreating a mammal for the lysosomal storage disorder alpha-mannosidosiscomprising subcutaneous injection of a composition of 50-300 mg/mllysosomal alpha-mannosidase.

Alpha-mannosidosis is a recessive, autosomal disease that occurs worldwide with a frequency of between 1/1.000.000 and 1/500.000. Mannosidosisis found in all ethnic groups in Europe, America, Africa and also Asia.It is detected in all countries with a good diagnostic service forlysosomal storage disorders, at a similar frequency. They are bornapparently healthy; however the symptoms of the diseases areprogressive. Alpha-mannosidosis displays clinical heterogeneity, rangingfrom very serious to very mild forms. Typical clinical symptoms are:mental retardation, skeletal changes, impaired immune system resultingin recurrent infections, hearing impairment and often the disease isassociated with a typical facial characteristics such as a coarse face,a prominent forehead, a flattened nasal bridge, a small nose, and abroad mouth. In the most severe cases (mannosidosis type I) the childrensuffer from hepatosplenomegaly, and they die during the first years oflife. Possibly this early death is caused by severe infections due tothe immunodeficiency caused by the disease. In milder cases(mannosidosis type 2) the patients usually reach adult age. The skeletalweaknesses of the patients result in the needs of wheeling chairs at age20 to 40. The disease causes a diffuse dysfunction of the brain oftenresulting in weak mental performances that excludes anything but themost basic skills of simple reading and writing. These problemsassociated with hearing inabilities and other clinical manifestationspreclude the patient from an independent life, the consequence beingthat life long caretaking is needed.

In yet another embodiment the present invention relates to a method oftreating a mammal for Krabbe disease comprising subcutaneous injectionof a composition of 50-300 mg/ml galactosylcerebrosidase.

In humans a deficiency in the GALC enzyme results in an autosomalinherited genetic Lysosomal Storage disease known as Krabbe disease orGloboid Cell Leukodystrophy. The enzyme is generally expressed in thetestis, kidneys, placenta, liver and brain of human beings and adeficiency in the GALC enzyme generally results in a disorder in themyelin metabolism and in the central and peripheral nervous systems (theCNS and PNS, respectively).

Krabbe disease has been observed in humans of any age, nationality andsex.

It should be noted that embodiments and features described in thecontext of one of the aspects of the present invention also apply to theother aspects of the invention. In particular, all of the embodimentsdescribed for the composition comprising a polypeptide of interest, suchas the presence of further compounds, buffers and pH also apply to thecomposition comprising a polypeptide of interest used in the presentapplications.

When an object according to the present invention or one of its featuresor characteristics is referred to in singular this also refers to theobject or its features or characteristics in plural. As an example, whenreferring to “a polypeptide” it is to be understood as referring to oneor more polypeptides.

Throughout the present specification the word “comprise”, or variationssuch as “comprises” or “comprising”, will be understood to imply theinclusion of a stated element, integer or step, or group of elements,integers or steps, but not the exclusion of any other element, integeror step, or group of elements, integers or steps.

All patent and non-patent references cited in the present application,are hereby incorporated by reference in their entirety.

The invention will now be described in further details in the followingnon-limiting Experimental sections.

EXPERIMENTAL

Materials

rhPBGD

The rhPBGD used in the following experiments were obtained according toprocess 2 in example 1 of WO 03/002731, where process 2 is the processwhich includes step IV, i.e. the ceramic hydroxyapatite chromatographystep.

Formulation Buffer

The recombinant and purified rhPBGD was present in the following aqueousformulation buffer:

3.67 mM Na₂HPO₄

27 mM Glycine

250 mM Mannitol

and a pH of 7.9

The formulation buffer was then sterile-filtered trough a 0.22 μmfilter.

Methods

Freeze-Drying

The freeze-drying of the purified rhPBGD solutions were performed in aLyostar (FTM-systems) freeze-drier according to the following schedule:

Freezing 0° C. 30 min 760 Torr phase   0° C. to −40° C. 1 ° C./min 760Torr −40° C.  30 min 760 Torr Primary −40° C. to 0° C. 1° C./min 169mTorr drying 0° C. 240 min 169 mTorr Secondary   0° C. to 30° C. 10°C./60 min, 20 mTorr drying 180 min 30° C.  720 min 20 mTorrVisual Observation (Clarity and Colour)

The liquid was visually studied with respect to colour, clarity andprecipitates according to the scheme below.

Colour: 1: No colour; 2: Slightly yellow; 3: Yellow

Clarity: 1: Clear; 2: Slightly turbid; 3: Turbid

Other remarks: Other observations from the operator were in someinstances included here (e.g. precipitates, undissolved material etc)

pH-Measurement

The pH-meter (Metrohm 691 pH Meter) and electrode (combined LL pHelectrode) were calibrated with 3 standard reference solutions (Merck)in the range 4.00 to 9.00. The liquid was finally analysed.

Protein Concentration

Protein concentration in extract, in-process samples, bulk drugsubstance and final product was determined by a method that utilizesprinciples of the reduction of Cu2+ to Cu+ by protein in an alkalinemedium (the Biuret reaction). The Cu+ ions were then reacted with areagent containing bicinchoninic acid resulting in a highly sensitiveand selective colorimetric detection.

Purity

Recombinant human Porphobilinogen Deaminase (rhPBGD) and rhPBGD variantswere separated according to their ability to adsorb and desorb to silicabased stationary media depending on the percentage of organic modifier(acetonitrile) in the mobile phase.

rhPBGD Activity

Porphobilinogen deaminase (PBGD) catalyzes the addition of 4 moleculesof porphobilinogen (PBG) to form a linear tetramer, preuroporphyrinogen,which is released from the enzyme and in vivo circularized touroporphyrinogen III by the action of Uroporphyrinogen III synthase.Preuroporphyrinogen can be chemically oxidized with benzoquinone to formuroporphyrin, which absorbs light at 405 nm.

The analyses were performed on one single vial on each test occasion.For the determination of rhPBGD activity and protein concentration thetests were performed in duplicate and triplicate respectively, for eachvial.

Osmolality

One vial of freeze-dried rhPBGD was resuspended in 1.00 ml MilliQ-water.The vial of frozen aqueous solution of rhPBGD was thawed. The osmometer(Vapro osmometer) was calibrated with 3 standard solutions in the range100-1000 mOsm/kg (100, 290, 1000 mOsm/kg). The liquid was then analyzed.

Example 1

Concentrating with Centrifugal Filter Devices

Frozen PBGD-bulk solution (7 mg/mL rhPBGD, 3.67 mM Na₂HPO₄, 27 mMglycine, 250 mM Mannitol, pH 7.9) was thawed in a water-bath at 20° C.,centrifuged at 3200 g for 10 min and thereafter sterile-filtrated by0.20 μm-PES filters (Nalgene Polyethersulfone filters). The PBGD-bulksolution was concentrated to 100 mg/ml by running the Centrifugal FilterDevices Centricon Plus-80 (Mw cut-off 30000) and Centricon Plus-15 (Mwcut-off 30000) at 3200 g for several hours. The concentrated solution,i.e. the retentate, was sterile-filtrated by 0.22 μm-filters (Millex GV)and finally a part of this solution was diluted with sterile formulationbuffer to get 50 mg/ml. The 5 mg/ml-solution was prepared by directlydiluting the recombinant and purified hPBGD with sterile formulationbuffer.

The 5 mg/mL, 50 mg/mL and 100 mg/mL rhPBGD were then freeze-dried asdescribed above. Several vials of each the above-mentioned freeze-driedrhPBGD solutions with 5, 50 and 100 mg/mL rhPBGD and of the aqueous 5mg/mL rhPBGD solution were stored at 40° C.±2° C., 75%±5% relativehumidity (RH). The vials were stored protected from light in a wellsealed secondary package (paper box).

At the indicated time points (i.e. time of storage) a vial of eachfreeze-dried samples were resuspended in 1.00 mL Millipore water.

Each of the resuspended vials and the aqueous vial of rhPBGd were thenvisually observed with regard to colour, clarity and precipitates, andthe pH, protein concentration, purity and rhPBGD activity were measuredas described above.

The results are given in the following tables 1-4:

TABLE 1 Freeze-dried product, 5 mg/mL Specific Time-point ActivityConcentration activity Purity Visual (month) (U/ml) (mg/ML) (U/mg) (%)observation 0 93.2 4.3 21.5 99.6 Colour: 1, clarity: 1 0.5 81.0 5.2 15.6ND Colour: 1, clarity: 1 1 76.6 5.9 13.1 99.9 Colour: 1, clarity: 1 1.587.0 5.5 15.9 99.7 Colour: 1, clarity: 1 2 53.3 4.7 11.4 99.6 Colour: 1,clarity: 1 3 50.8 4.8 10.7 99.6 Colour: 1, clarity: 1 6 34.3 5.3 6.599.6 Colour: 1, clarity: 1

TABLE 2 freeze-dried product; 50 mg/ml Specific Time-point ActivityConcentration activity Purity Visual (month) (U/ml) (mg/ML) (U/mg) (%)observation 0 888 41.4 21.5 99.1 Colour: 2, clarity: 1 0.5 842 50.6 16.6ND Colour: 2, clarity: 1 1 746 50,6 14.8 100 Colour: 2, clarity: 1 2 64052.9 12.1 100 Colour: 2, clarity: 1 3 634 49.0 12.9 100 Colour: 2,clarity: 1 6 422 43.0 9.8 100 Colour: 2, clarity: 1

TABLE 3 Freeze-dried product; 100 mg/ml Specific Time-point ActivityConcentration activity Purity Visual (month) (U/ml) (mg/ML) (U/mg) (%)observation 0 1944 83.7 23.2 99.1 Colour: 3, clarity: 1 1 1470 98.7 14.9100 Colour: 3, clarity: 1 2 1282 94.8 13.5 100 Colour: 3, clarity: 1 31253 82.6 15.2 100 Colour: 3, clarity: 1 6 739 75.5 9.8 100 Colour: 3,clarity: 1

TABLE 4 Aqueous product; 5 mg/ml Specific Time-point ActivityConcentration activity Purity Visual (month) (U/ml) (mg/ML) (U/mg) (%)observation 0 95.6 4.0 23.7 99.1 Colour: 1, clarity: 1 0.5 48.1 5.4 8.9ND Colour: 1, clarity: 1 1 28.6 5.9 4.8 96.1 Colour: 1, clarity: 1 1.512.3 5.6 2.2 91.4 Colour: 1, clarity: 1 2 4.5 4.4 1.0 90.7 Colour: 1,clarity: 1 3 7.1 3.1 2.3 87.3 Colour: 2, clarity: 2 6 4.4 2.1 2.1 58.1Colour: 2, clarity: 2

Example 2

Concentrating a rhPBGD Composition by Centrifugal Filter Devices

Frozen PBGD-bulk solution (7 mg/mL rhPBGD, 3.67 mM Na₂HPO₄, 27 mMglycine, 250 mM Mannitol, pH 7.9) was thawed in a water-bath at 20° C.,centrifuged at 3200 g for 10 min and thereafter sterile-filtrated by0.20 μm-PES filters (Nalgene Polyethersulfone filters). The PBGD-bulksolution was concentrated to 100 mg/ml by running the Centrifugal FilterDevices Centricon Plus-80 (Mw cut-off 30000) and Centricon Plus-15 (Mwcut-off 30000) at 3200 g for several hours. The concentrated solution,i.e. the retentate,

was sterile-filtered by 0.22 μm-filters (Millex GV) and diluted withsterile filtered formulation buffer (see above) to get solutions oflower concentrations. A fraction in volume of each concentration wasfreeze-dried as described above.

The different concentrations of freeze-dried rhPBGD and aqueous solutionof rhPBGD were stored at 5° C.±3° C. or at −20° C.±5° C. (ambientrelative humidity (RH)). All vials were stored protected from light in awell-sealed secondary package (paper box).

At the indicated time points (i.e. time of storage) a vial of eachfreeze-dried samples were resuspended in 1.00 mL Millipore water andthen tested together with the aqueous solution of rhPBGD by visuallyobserving the colour, clarity and precipitates, and by measuring pH,protein concentration, purity, osmolality and rhPBGD activity.

The results are given in the following tables 5-19:

TABLE 5 Aqueous product; 11 mg/ml; Storage temp.: +5° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 10.9 255.0 23.4 100.07.80 290 Colour: 2 Clarity: 1 Clear None/few 1 9.5 216.8 22.8 100.0 7.81305 Colour: 2 Clarity: 1 Clear None/few 2 10.9 230.2 21.1 98.0 7.80 300Colour: 2 Clarity: 1 Clear None/few 3 11.2 226.6 20.2 100.0 7.76 290Colour: 2 Clarity: 1 Clear Few 6 14.7 271.1 18.4 100.0 7.77 300 Colour:2Clarity: 1 Clear Several

TABLE 6 Aqueous product: 11 mg/ml; Storage temp: −20° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 10.4 236.1 22.6 100 7.80290 Colour: 2 Clarity: 1 Clear None 1 11.7 270.3 23.1 100 7.81 302Colour: 2 Clarity: 1 Clear None 2 ND ND ND ND ND ND ND 3 12.4 247.7 20.0100 7.77 288 Colour: 2 Clarity: 1 Clear None 6 13.4 291.5 21.8 100 7.77301 Colour: 2 Clarity: 1 Clear None

TABLE 7 Freeze-dried product, 11 mg/ml; Storage temp.: +5° C. Spe-Visual Pro- cific observation tein activ- Osmo- Colour 1-3; Time- conc.Activ- ity Puri- lality Clarity 1-3; point (mg/ ity (U/ ty (mOsm/Solution; (month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 10.9 230.0 21.2100.0 7.80 290 Colour: 2 Clarity: 1 Clear None 1 ND ND ND ND ND ND ND 2ND ND ND ND ND ND ND 3 13.3 269.3 20.2 100.0 7.74 282 Colour: 2 Clarity:1 Clear None 6 14.7 237.9 16.2 100.0 7.76 290 Colour: 2 Clarity: 1 ClearNone

TABLE 8 Aqueous product, 17 mg/ml; Storage temp.: +5° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 18.0 471.0 26.1 100.07.80 298 Colour: 2 Clarity: 1 Clear None/few 1 17.5 360.4 20.6 100.07.81 311 Colour: 2 Clarity: 1 Clear None/few 2 18.3 397.0 21.7 100.07.83 302 Colour: 2 Clarity: 1 Clear None/few 3 16.6 376.5 22.7 100.07.77 294 Colour: 2 Clarity: 1 Clear Few 6 16.0 257.3 16.1 100.0 7.76 305Colour: 2 Clarity: 1 Clear Several

TABLE 9 Aqueous product, 17 mg/ml; Storage temp.: −20° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 17.9 411.6 23.0 100.07.80 298 Colour: 2 Clarity: 1 Clear None 1 17.4 439.5 25.3 100.0 7.80310 Colour: 2 Clarity: 1 Clear None 2 ND ND ND ND ND ND ND 3 16.4 389.423.7 100.0 7.77 292 Colour: 2 Clarity: 1 Clear None 6 18.0 373.8 20.8100.0 7.76 305 Colour: 2 Clarity: 1 Clear None

TABLE 10 Freeze-dried product, 17 mg/ml; Storage temp.: 5° C. Spe-Visual Pro- cific observation tein activ- Osmo- Colour 1-3 Time- conc.Activ- ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/Solution (month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 16.9 380.1 22.5100.0 7.80 298 Colour: 2 Clarity: 1 Clear None 1 ND ND ND ND ND ND ND 2ND ND ND ND ND ND ND 3 15.6 391.9 25.1 100.0 7.76 285 Colour: 2 Clarity:1 Clear None 6 16.6 341.3 20.6 100.0 7.75 297 Colour: 2 Clarity: 1 ClearNone

TABLE 11 Aqueous product; 36 mg/ml; Storage temp.: +5° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 36.0 844.4 23.4 100.07.81 305 Colour: 2 Clarity: 1 Clear None/few 1 35.5 778.1 21.9 100.07.82 314 Colour: 2 Clarity: 1 Clear None/few 2 35.4 798.5 22.6 100.07.81 310 Colour: 2 Clarity: 1 Clear None/few 3 28.9 687.9 23.8 100.07.77 303 Colour: 2 Clarity: 1 Clear Few 6 37.2 537.3 14.4 100.0 7.77 312Colour: 2 Clarity: 1 Clear Several

TABLE 12 Aqueous product, 36 mg/ml; Storage temp.: −20° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 34.0 853.4 25.1 100.07.81 305 Colour: 2 Clarity: 1 Clear None 1 38.0 853.6 22.5 100.0 7.83321 Colour: 2 Clarity: 1 Clear None 2 ND ND ND ND ND ND ND 3 31.6 776.324.6 100.0 7.76 299 Colour: 2 Clarity: 1 Clear None 6 30.6 543.8 17.8100.0 7.75 311 Colour: 2 Clarity: 1 Clear None

TABLE 13 Freeze-dried product, 36 mg/ml; Storage temp.: 5° C. Spe-Visual Pro- cific observation tein activ- Osmo- Colour 1-3 Time- conc.Activ- ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/Solution (month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 29.5 657.0 22.3100.0 7.81 305 Colour: 2 Clarity: 1 Clear None 1 ND ND ND ND ND ND ND 2ND ND ND ND ND ND ND 3 28.7 747.6 26.0 100.0 7.75 290 Colour: 2 Clarity:1 Clear None 6 29.8 579.3 19.4 100.0 7.76 300 Colour: 2 Clarity: 1 ClearNone

TABLE 14 Aqueous product, 50 mg/ml; Storage temp.: 5° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 46.2 780.9 16.9 96.3 7.59317 Colour: 3 Clarity: 1 Slightly opalescent None 1 47.9 915 19.1 907.58 305 Colour: 3 Clarity: 1 Slightly opalescent None 2 47.2 898.3 19.0100 7.60 318 Colour: 3 Clarity: 1 Slightly opalescent None 3 60.8 1102.618.1 100 7.72 314 Colour: 3 Clarity: 1 Clear None 6 62.5 902.8 14.4 1007.60 331 Colour: 3 Clarity: 2 Clear None 9 41.7 618.5 14.8 100 7.60 336Colour: 3 Clarity: 2 Clear None 12 50.2 540.8 10.8 97.5 7.60 329 Colour:3 Clarity: 2 Clear None

TABLE 15 Aqueous product, 50 mg/ml; Storage temp.: −20° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 46.2 780.9 16.9 96.3 7.59317 Colour: 3 Clarity: 1 Slightly opalescent None 1 47.2 899.1 19.0 93.77.58 313 Colour: 3 Clarity: 1 Slightly opalescent None 2 53 1222.7 23.1100.0 7.60 315 Colour: 3 Clarity: 1 Slightly opalescent None 3 61.21336.2 21.8 100.0 7.75 320 Colour: 3 Clarity: 1 Slightly opalescent None6 52.2 1001.3 19.2 100.0 7.60 321 Colour: 3 Clarity: 1 Slightlyopalescent None 12 50.4 887.9 17.6 100.0 7.60 320 Colour: 3 Clarity: 1Slightly opalescent None

TABLE 16 Freeze-dried product, 50 mg/ml; Storage temp.: 5° C. Spe-Visual Pro- cific observation tein activ- Osmo- Colour 1-3 Time- conc.Activ- ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/Cake/solution (month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 42.7 759.417.8 100.0 7.58 292 Colour: 3 Clarity: 1 Cake: yellow, some cracksSolution: Clear None 1 42.6 840.4 19.7 63.1 7.58 293 Colour: 3 Clarity:1 Cake: yellow, some cracks Solution: Clear None 2 42.1 937.0 22.3 100.07.60 292 Colour: 3 Clarity: 1 Cake: yellow, some cracks Solution: ClearNone 3 47.4 1014.7 21.4 100.0 7.75 291 Colour: 3 Clarity: 1 Cake:yellow, some cracks Solution: Clear None 6 49.0 876.5 17.9 100.0 7.60304 Colour: 3 Clarity: 1 Cake: yellow, some cracks Solution: Clear None12 51.3 945.0 18.4 100.0 7.60 308 Colour: 3 Clarity: 1 Cake: yellow,some cracks Solution: Clear None

TABLE 17 Aqueous product, 100 mg/ml; Storage temp.: 5° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) PH kg) Aggregates 0 81.8 1705.7 20.9 99.97.60 350 Colour: 3 Clarity: 1 Slightly opalescent None 1 85.9 1942.422.6 96.9 7.55 352 Colour: 3 Clarity: 1 Slightly opalescent None 2 95.71690.8 17.7 96.9 7.65 357 Colour: 3 Clarity: 1 Slightly opalescent None3 104.3 1671.2 16.0 100.0 7.65 350 Colour: 3 Clarity: 1 Slightlyopalescent None 6 96.0 1642.6 17.1 100.0 7.62 360 Colour: 3 Clarity: 1Slightly opalescent None 9 102.8 1270.8 12.4 100.0 7.63 352 Colour: 3Clarity: 2 Slightly opalescent None 11 86.2 1140.2 13.2 100.0 7.60 353Colour: 3 Clarity: 2 Slightly opalescent None 12 113.9 1550.6 13.6 100.07.58 350 Colour: 3 Clarity: 2 Slightly opalescent None 15 114.7 1160.610.1 98.3 7.61 350 Colour: 3 Clarity: 2 Slightly opalescent None 18 86.2907.4 10.5 100.0 7.67 340 Colour: 3 Clarity: 2 Slightly opalescent None

TABLE 18 Aqueous product, 100 mg/ml; Storage temp.: −20° C. Spe- VisualPro- cific observation tein activ- Osmo- Colour 1-3 Time- conc. Activ-ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/ Solution(month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 81.8 1705.7 20.9 99.97.60 316 Colour: 3 Clarity: 1 Slightly opalescent None 1 89.3 2108.823.6 100.0 7.56 350 Colour: 3 Clarity: 1 Slightly opalescent None 2112.0 2066.5 18.5 100.0 7.65 353 Colour: 3 Clarity: 1 Slightlyopalescent None 3 100.2 2172.4 21.7 96.7 7.65 352 Colour: 3 Clarity: 1Clear None 6 87.5 2672.3 30.6 100.0 7.62 352 Colour: 3 Clarity: 1 ClearNone 9 97.1 2040.3 21.0 100.0 7.62 353 Colour: 3 Clarity: 1 Clear None11 104.6 2234.0 21.4 100.0 7.60 353 Colour: 3 Clarity: 1 Clear None 1294.5 1608.8 17.0 100.0 7.57 350 Colour: 3 Clarity: 1 Slightly opalescentNone 15 118.0 2015.9 17.1 100.0 7.62 351 Colour: 3 Clarity: 1 Slightlyopalescent None 18 90.6 1736.4 19.2 100.0 7.69 338 Colour: 3 Clarity: 1Slightly opalescent None

TABLE 19 Freeze-dried product, 100 mg/ml; Storage temp.: 5° C. Spe-Visual Pro- cific observation tein activ- Osmo- Colour 1-3 Time- conc.Activ- ity Puri- lality Clarity 1-3 point (mg/ ity (U/ ty (mOsm/Cake/solution (month) ml) (U/ml) mg) (%) pH kg) Aggregates 0 76.0 1638.321.5 100.0 7.60 316 Colour: 3 Clarity: 1 Cake: Yellow, some cracksSolution: Clear None 1 71.6 1747.6 24.4 100.0 7.55 318 Colour: 3Clarity: 1 Cake: Yellow, some cracks Solution: Clear None 2 81.6 1769.921.7 100.0 7.63 313 Colour: 3 Clarity: 1 Cake: Yellow, some cracksSolution: Clear None 3 84.1 1616.6 19.2  98.2 7.65 320 Colour: 3Clarity: 1 Cake: Yellow, some cracks Solution: Clear None 6 96.7 2197.622.7 100.0 7.60 324 Colour: 3 Clarity: 1 Cake: Yellow, some cracksSolution: Clear None 9 ND ND ND ND ND ND ND 12 96.0 1978.4 20.6 100.07.57 322 Colour: 3 Clarity: 1 Cake: Yellow, some cracks Solution: ClearNone 15 ND ND ND ND ND ND ND 18 80.6 1602.6 19.9 100.0 7.75 310 Colour:3 Clarity: 1 Cake: Yellow, some cracks Solution: Clear None

Example 3

Concentrating a rhPBGD Composition by Tangential Flow Filtration (TFF)

The bulk solution of rhPBGD was then thawed for a minimum of three daysat 5° C. and in darkness.

The thawed solution was then centrifuged with 200 mL conical centrifugetubes for approximately 10 minutes at 2200 g.

The solution was then filtered through a series of filters with thefollowing pore-sizes: 5.0 μm; 0.65 μm; 0.45 μm and 0.20 μm before it wasconcentrated by tangential flow filtration (TFF).

The concentration by TFF was performed with a Millipore Labscale TFFSystem and Millipore Pellicon® XL Filter with a pump inlet pressure ofapproximately 20-25 psi and a pressure over the Pellicon® XL Filter ofapproximately 4-6 psi. The rhPBGD was protected from light during theprocedure by covering the sample container of the TFF System by sheetsof aluminium foil.

The concentrated rhPBGD solution obtained from the TFF procedure wasthen buffer-changed against a formulation buffer containing 3.67 mMNa₂HPO₄×₂H₂O, 27 mM glycin and 220 mM Mannitol prepared in sterilewater. This was performed by continuously adding said buffer to theTFF-system and pressing it across the membrane until said buffer hasreplaced the previous buffer.

The concentrated and buffer-changed rhPBGD solution was then sterilefiltered by passing it through a filter with a pore-size of 0.22 μm.This sterile filtration was performed twice with a new filter each time.

The sterile concentrated rhPBGD solution was then placed in vials beforeit was freeze-dried as described in the method section.

Example 4

The Effect of Different Modes of Freeze-Drying and/or the Amount ofExcipients on the Reconstitution Time

PBGD was concentrated as described in example 3 and after the exchangeof the buffer was the concentration of PBGD determined.

The concentrated PBGD solution was then freeze-dried in a Lyostar(FTM-systems) freeze-dryer. The solutions were filled in 2 and 6 mlinjection glass vials (type 1) and stoppered with rubber stoppers(chlorobutyl).

Original Freeze-Drying Cycle:

The samples were loaded in ambient temperature and the shelves werecooled down to 0° C. for 30 minutes. The temperature were lowered to−40° C. (1° C. per minute) and held there for 30 minutes and then thevacuum pressure was drawn to 126 mTorr and the primary drying began byraising the temperature to 0° C. (1° C. per minute). After 360 minutesof primary drying the temperature was raised to +30° C. (0.5° C. perminute) and full vacuum was drawn simultaneously (start of secondarydrying). The temperature was held at +30° C. for 360 minutes and thevials were then stoppered under vacuum.

Freeze-Drying with Inclusion of an Annealing Step:

After 30 minutes at −40° C. the temperature was raised with a rate of 2°C. per minute to −10° C. or −20° C. at which temperature they were keptfor 120 or 420 minutes before the temperature was lowered again with 2°C. per minute to −40° C. were the samples were kept for 60-90 minutesbefore start of primary drying.

The results are shown in Table 20 where the short terms used with regardto the excipients and the freeze-drying cycle mean the following:

1× amount of excipients refers to that the PBGD solution comprises 3.67mM Na₂HPO₄×2H₂O, 27 mM glycin and 220 mM Mannitol prepared in sterilewater.

1.5× amount excipients refers to that the PBGD solution comprises 5.51mM Na₂HPO₄×2H₂O, 40.5 mM glycin and 375 mM Mannitol prepared in sterilewater, i.e. 1.5× of each of the components present in the 1× buffer.

2× excipients refers to that the PBGD solution comprises 7.34 mMNa₂HPO₄×2H₂O, 54 mM glycin and 500 mM Mannitol prepared in sterilewater, i.e. 2× of each of the components present in the 1× buffer.

The original freeze-drying cycle is as described above.

The annealing freeze-drying cycle is as described above where theannealing step comprises raising the temperature to −10° C. at keepingthe sample at this temperature for 120 minutes before lowering it to−40° C. again.

The extended annealing freeze-drying cycle is as described above wherethe annealing step comprises raising the temperature to −20° C. atkeeping the sample at this temperature for 420 minutes before loweringit to −40° C. again.

TABLE 20 Reconstitution time for Protein different free-drying cyclesAmount of concentration Extended excipients (mg/ml) Original Annealingannealing 1x 198 600 550 480 1x 175 540 500 450 1x 150 450 480 180 1x125 330 100 10 1x 100 40 10 10 1x 80 25 10 10 1.5x  200 480 40 60 1.5x 175 220 10 10 1.5x  150 60 10 10 1.5x  125 15 10 10 1.5x  100 10 10 102x 200 120 20 2x 175 40 20 2x 150 20 10 2x 100 10 10

Example 5

The Effect of Different Modes of Freeze-Drying and/or the Amount ofExcipients on the Appearance of the Freeze-Dried Product

Concentrated and freeze-dried solutions of PBGD were prepared asdescribed in example 4 and references to the amount of excipients andthe type of freeze-drying cycle has the same meaning as in example 4.

The following results were obtained by visual inspection of thefreeze-dried products:

A: Comparison of three products prepared from solutions comprisingrespectively, 4.6 mg/ml 66.6 mg/ml and 109.4 mg/ml rhPBGD showed thatthe number of cracks in the freeze-dried product increased asconcentration of rhPBGD increased.

B: Comparison of two products, prepared from a solution comprising 150mg/ml rhPBGD, and comprising 1× and 1.5× amount of excipients showedthat the number of cracks in the freeze-dried product was lower for theproduct which comprised 1.5× amount of excipients than the productcomprising 1× amount of excipients.

C: Comparison of two freeze-dried products prepared from a 150 mg/mlrhPBGD solution, comprising 1× and 2× amount of excipients showed thatthe number of cracks in the freeze-dried product with 2× amount ofexcipients was lower than the product comprising the 1× amount ofexcipients.

D: Comparison of three freeze-dried products prepared from a 150 mg/mlrhPBGD solution by using the original, the annealing and the extendedannealing freeze-drying cycle showed that the number of cracks in thefreeze-dried product was lower in the product which was preparedaccording to the annealing freeze-drying cycle than in the productprepared according to the original freeze-drying cycle. Furthermore, thenumber of cracks in the product prepared according to the extendedannealing freeze-drying cycle was lower than in the product preparedaccording to the annealing freeze-drying cycle.

E: Three freeze-dried products were prepared from a 150, 175 and 200mg/ml, respectively, rhPBGD solution. The freeze-dried products eachcomprised 1.5× amount of excipients and they were freeze-dried with theannealing cycle. None of the freeze-dried products comprised any cracks.

F: Two freeze-dried rhPBGD products were prepared from a 150 mg/mlrhPBGD solution. One of them comprised 1× amount of excipients and wasprepared according to the original freeze-drying cycle, while the othercomprised 1.5× amount of excipients and was prepared according to theextended annealing free-drying cycle. The product comprising 1.5× amountof excipients and prepared according to the extended annealingfreeze-drying cycle comprised fewer cracks than the product comprising1× amount of excipients and prepared according to the originalfreeze-drying cycle.

G: Two freeze-dried rhPBGD products were prepared from a 150 mg/mlrhPBGD solution. One of them comprised 1× amount of excipients and wasprepared according to the original freeze-drying cycle, white the othercomprised 0.1% Tween 80 in combination with the 1× amount of excipientsand was prepared according to the extended annealing freeze-dryingcycle. The product comprising the 0.1% Tween 80 in combination with the1× amount of excipients and which was prepared according to the extendedannealing freeze-drying cycle comprised fewer cracks than the productwhich comprised 1× amount of excipients and which was prepared accordingto the original freeze-drying cycle.

Example 6

The Effect of Recovery Volume, the Amount of Excipients and the Mode ofFreeze-Drying on the Stability of Freeze-Dried rhPBGd

Concentrated rhPBGD solutions freeze-dried samples were prepared asdescribed in example 4.

The “bulk solution” is a concentrated solution of PBGD beforefreeze-drying.

Table 21 shows the results of rhPBGD solutions having the followingcharacteristics with regard to the concentration of rhPBGD, amount ofexcipients (were the same definitions as in example 4 are used), themode of freeze-drying (were the same definitions as in example 4 areused) and the ratio of the filling volume (fill. Vol which is the volumeof the composition before it is freeze-dried) versus the recovery volume(Rec. vol which is the volume in which the freeze-dried product isresuspended):

Solution 1:

-   -   Approximately 5 mg/ml rhPBGD    -   1× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=Rec. vol        Solution 2:    -   Approximately 70 mg/ml rhPBGD    -   1× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=2× Rec. vol        Solution 3:    -   Approximately 110 mg/ml rhPBGD    -   1× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=Rec. vol        Solution 4:    -   Approximately 70 mg/ml rhPBGD    -   1× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=1.5× Rec. vol        Solution 5:    -   Approximately 90 mg/ml rhPBGD    -   ⅔× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=1.5× Rec. vol        Solution 6:    -   Approximately 60 mg/ml rhPBGD    -   ½× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=2× Rec. vol        Solution 7:    -   Approximately 110 mg/ml rhPBGD    -   1× amount of excipient    -   Annealing freeze-drying cycle    -   Fill. vol=Rec. vol        Solution 8:    -   Approximately 60 mg/ml rhPBGD    -   1× amount of excipient    -   Annealing freeze-drying cycle    -   Fill. vol=2× Rec. vol        Solution 9:    -   Approximately 150 mg/ml rhPBGD    -   1× amount of excipient    -   Annealing freeze-drying cycle    -   Fill. vol=Rec. vol        Solution 10:    -   Approximately 150 mg/ml rhPBGD    -   1× amount of excipient    -   Original freeze-drying cycle    -   Fill. vol=Rec. vol

Although not shown in Table 21 the purity was also tested for each timepoint as was found to 100% in all cases.

For solution 2 at the week 4 and 9 time point and for solution 4 theweek 9 time point a wrong recovery volume was used.

TABLE 21 Measuring Protein Specific point Fill. Vol Rec. Vol Osmolalityconcentration Activity activity Solution (week) (ml) (ml) pH (mosmol/kg)(mg/ml) (U/ml) (U/mg) 1 bulk 4.6 78 17.1 0 0.67 0.67 7.54 274 4.8 8517.8 2 0.67 0.67 7.22 274 4.6 87 19.4 4 0.67 0.67 7.78 279 5.1 75 14.5 70.67 0.67 7.87 284 5.1 68 13.3 9 0.67 0.67 7.67 403 7.0 93 13.2 2 bulk66.6 1129 16.9 0 0.67 0.335 7.64 525 113 1915 16.9 2 0.67 0.335 7.63 45993.6 1593 17.0 4 0.67 0.67 7.75 264 64.6 1104 17.1 7 0.67 0.335 7.95 451106.4 2106 19.8 9 0.67 0.67 7.59 247 51.4 859 16.7 3 bulk 109.4 149113.6 0 0.67 0.67 7.75 274 99.9 1598 16.0 2 0.67 0.67 7.64 269 91.4 154316.9 4 0.67 0.67 7.68 274 101.2 1825 18.0 7 0.67 0.67 7.71 278 103.42045 19.8 9 0.67 0.67 7.67 274 88.3 1656 18.8 4 bulk 71.5 1244 17.4 00.67 0.45 7.64 448 113.8 1748 15.4 2 0.67 0.45 7.63 411 86.4 1806 20.9 40.67 0.45 7.77 362 109.9 1897 17.3 7 0.67 0.45 7.90 379 95.2 686 (7.2) 90.67 0.67 7.63 273 59.7 1090 18.3 5 bulk 91.0 1610 17.7 0 0.67 0.45 7.65296 119.4 2014 16.9 2 0.67 0.45 7.61 285 112.3 2093 18.6 4 0.67 0.457.90 292 125.1 2409 19.3 7 0.67 0.45 7.88 297 116.4 1928 16.6 9 0.670.45 7.34 278 102.5 1490 14.5 6 bulk 60.7 992 16.3 0 0.67 0.335 7.63 295112.6 1753 15.6 2 0.67 0.335 7.60 288 86.9 1787 20.6 4 0.67 0.335 7.83287 116.4 2106 18.1 7 0.67 0.335 8.20 299 109.7 695 (6.3) 9 0.67 0.3357.44 287 95.2 1636 17.2 7 bulk 116.4 1926 16.5 0 0.67 0.67 7.56 275101.1 1750 17.3 2 0.67 0.67 7.51 276 93.4 1831 19.6 4 0.67 0.67 7.60 270101.6 1774 17.5 7 0.67 0.67 7.53 283 102.2 1639 16.0 9 0.67 0.67 7.46274 89.9 960 10.7 8 bulk 64.5 1119 17.4 0 0.67 0.335 7.52 511 100.7 171817.1 2 0.67 0.335 7.51 459 99.3 1900 19.1 4 0.67 0.335 7.70 482 114.51913 16.7 9 0.67 0.335 7.29 425 102.3 1650 16.1 9 bulk 165 3587 21.7 00.60 0.60 7.71 309 121.4 2819 23.2 4 0.60 0.60 7.74 — 140.3 2014 14.4  7.5 0.60 0.60 7.61 292 135.9 1640 12.1 10 bulk 165 3587 21.7 0 0.600.60 7.86 276 142.1 2397 16.9 3 0.40 0.40 8.20 314 141.9 2381 16.8 50.60 0.60 7.60 302 131.8 2304 17.5

Example 7

Effect of Different Excipients on the Stability of rhPBGD

rhPBGD was concentrated as described in example 4 and then the bufferwas changed as to one of the four buffers described below. The productswere then freeze-dried as described in example 4 with an originalannealing step included and the stability of the samples were tested asdescribed in example 6.

The effect of the following four formulations on the stability of rhPBGDwas tested:

Formulation A (corresponds to solution 9 in example 6): 250 mM mannitol,27 mM glycine and 3.67 mM Na₂HPO₄.

Formulation B: 250 mM mannitol, 27 mM glycine and 10 mM TRIS-HCL.

Formulation C: 250 mM mannitol, 27 mM glycine, 3.67 mM Na₂HPO₄ and 0.1%Tween 80.

Formulation D: 221 mM mannitol, 29 mM sucrose, 27 mM glycine, 3.67 mMNa₂HPO₄ and 0.1% Tween 80.

The results are shown in Table 22.

TABLE 22 Measuring Protein Specific point Fill. Vol Rec. Vol Osmolalityconcentration Activity activity Formulation (week) (ml) (ml) pH(mosmol/kg) (mg/ml) (U/ml) (U/mg) A Bulk 7.69 366 165 3587 21.7 0 0.600.60 7.71 309 121.4 2819 23.2 4 0.60 0.60 7.74 — 140.3 2014 14.4 7.50.60 0.60 7.61 292 135.9 1640 12.1 B Bulk 7.54 320 173 3595 20.8 0 0.600.60 7.58 284 148.1 3726 25.2 3 0.60 0.60 7.57 280 165.4 2947 17.8 40.60 0.60 7.69 — 167.5 2367 14.1 7.5 0.60 0.60 7.60 283 150.4 2235 14.9C Bulk 7.40 338 178 3606 20.2 0 0.60 0.60 7.76 290 142.9 2662 18.6 30.60 0.60 7.43 285 181.7 2332 12.8 4 0.60 0.60 7.42 — 173.1 1436 8.3 60.60 0.60 7.55 274 156.6 1254 7.4 7.5 0.60 0.60 7.34 274 141.5 1252 8.9D Bulk 7.41 337 175 3869 22.1 0 0.60 0.60 7.80 292 127.5 2355 18.5 30.60 0.60 7.35 288 143.9 1988 13.8 4 0.60 0.60 7.26 — 159.3 1644 10.3 60.60 0.60 7.30 281 135.7 1236 9.1 7.5 0.60 0.60 7.28 282 125.7 1146 9.1

The invention claimed is:
 1. A method of concentrating a solution, themethod comprising: (a) providing a solution that comprises α-mannosidaseor an analogue thereof, wherein the analogue has (i) at least 95%sequence identity to the α-mannosidase of SEQ ID NO: 21 and (ii) atleast 50% of the activity of the α-mannosidase; (b) removingα-mannosidase aggregates from the solution by centrifugation orfiltration; and then (c) concentrating the solution, wherein theconcentrated solution (i) is isotonic to mammalian tissue, (ii)comprises at least 25 mg/ml of the α-mannosidase or analogue, and (iii)comprises less than 5% w/w aggregated α-mannosidase or analogue based onthe total α-mannosidase or analogue in the concentrated solution.
 2. Themethod of claim 1, wherein the α-mannosidase comprises amino acidsequence SEQ ID NO.
 21. 3. The method of claim 1, wherein theconcentrating step is performed by freeze-drying or evaporation.
 4. Themethod of claim 1, wherein the concentrating step is performed byultrafiltration.
 5. The method of claim 1, wherein the concentratingstep is performed by tangential flow filtration.
 6. The method of claim1, wherein the concentrating step is performed by a centrifugal device.7. The method of claim 1, wherein the solution further comprises one ormore of glycine, L-serine, sucrose, or mannitol.
 8. The method of claim1, wherein the solution further comprises one or more buffers selectedfrom the group consisting of: TRIS-HCL, Na-citrate, and Na₂HPO₄.
 9. Themethod of claim 1, wherein the method further comprises sterilizing theconcentrated solution.
 10. The method of claim 1, wherein the methodfurther comprises freeze-drying the concentrated solution.
 11. Themethod of claim 1, wherein the centrifugation is performed at 1800-2500g.
 12. The method of claim 1, wherein the filtration is with a filterthat has a pore-size from about 0.20 to about 5.0 micrometer.
 13. Themethod of claim 1, wherein the α-mannosidase or analogue thereof is arecombinant protein.
 14. The method of claim 1, wherein said methodfurther comprises one or more of the following steps prior to step a):i) recombinantly expressing the α-mannosidase or the analogue thereof ina prokaryotic or vertebrate cell; ii) purifying the α-mannosidase or theanalogue thereof in a formulation buffer; and iii) exchanging theformulation buffer.
 15. The method according to claim 14, whereinpurifying comprises subjecting the α-mannosidase or the analogue thereofto one or more of affinity chromatography, ion exchange chromatographyor hydroxyapatite chromatography.
 16. The method according to claim 14,wherein the purifying comprises subjecting the α-mannosidase or theanalogue thereof to affinity chromatography and then subjecting theα-mannosidase or the analogue thereof to ion exchange chromatography.17. The method according to claim 16, wherein the purifying furthercomprises subjecting the α-mannosidase or the analogue thereof to ahydroxyapatite column after subjecting the α-mannosidase or the analoguethereof to the ion exchange chromatography.
 18. The method according toclaim 14, wherein the recombinant expression is with a nucleic acidsequence comprising a sequence selected from the group consisting of (i)SEQ ID NO: 22 and (ii) a nucleic acid sequence which is at least 95%identical to SEQ ID NO:
 22. 19. The method according to claims 16,wherein said method further comprises a step of dilution ordiafiltration of the α-mannosidase or the analogue thereof after theaffinity chromatography but before the ion exchange chromatography.